1) On 30 June 1908, something exploded five miles above Tunguska in deepest Siberia with the force of a 12.5 megaton nuclear bomb. It left no crater, but trees were scorched and flattened over a vast area. Livid sunsets were seen round the world for weeks. A layer of black dust suggested cometary origin - possibly a fragment of Comet Encke.
2) On New Year's Day 1984, a dud, 9in, 22lb, Second World War shell crashed from a sunny sky into a backyard in Lakewood, 20 miles southwest of Los Angeles, leaving a 4ft crater. Neighbours had heard a whistling sound but had seen and heard no plane. This fall echoed a similar event in Naples, Italy, on 7 February 1958, when an artillery shell, dated 1942, with a cross and eagle design, fell from the sky.
3) In July 1975, Erskine Lawrence Ebbin was knocked off his moped and killed by a taxi in Hamilton, Bermuda. It was the same taxi with the same driver, carrying the same passenger, that had killed his brother Neville in July the previous year. Both brothers were 17 when they died, and had been riding the same moped in the same street.
4) Unidentified flying objects are as old as recorded history, but the "flying saucer" age began in the summer of 1947. On 24 June that year, pilot Kenneth Arnold spotted nine semi-circular "aircraft" over the Cascade Mountains in Washington State. In an interview he likened their motion to that of a saucer skipped across water; the phrase "flying saucer" seems to have been coined simultaneously by several sub-editors soon afterwards. A torrent of similar reports poured forth, including more than 1,000 in the second half of 1947 in America alone.
5) The first famous "alien abduction" - of Betty and Barney Hill, in New Hampshire - took place on 19 September 1961. (Many Americans believe that millions of their compatriots have been temporarily seized by aliens for medical examinations and procreation. The subject is both complex and contentious; why should the aliens concentrate so heavily on Americans, for instance?)
6) Those claiming contact with aliens in the Fifties, notably the American George Adamski, usually described benevolent beings, unlike the sinister "Greys" of recent years; but there were exceptions. On 28 November 1954, Gustava Gonzalez and Jose Ponce encountered a hovering luminous sphere in the suburbs of Caracas, Venezuela. Gonzalez was knocked 15ft by a hairy, dwarf-like creature. Another blinded him with a light beam. Ponce saw two more emerge from the bushes, carrying earth and rocks, and leap into the hovering sphere. Both men were placed under medical observation for several days.
7) On 21 May 1921, thousands of frogs fell on Gibraltar during a thunder- storm - just one among many falls of frogs and fish to have puzzled scientists throughout the century. On 4 March 1998, for example, a shower in Shirley, Croydon, south London, included a large number of dead frogs. Weathermen offered the traditional explanation that they had been sucked up from a pond by a waterspout; however, as has often been objected in the past, it is a bizarre tornado that can pick up one type of animal from a pool to the exclusion of all others.
8) On 23 October 1947, ichthyologist Dr AD Bajkov saw fresh, dead minnows and black bass lying on the street outside the cafe where he was having breakfast in Biloxi, Mississippi, just after a rain-shower. His report appeared in Science in 1949. More recently, dozens of fish were found in gardens and on roofs in the borough of Newham, east London, following a thunderstorm on the night of 27-28 May 1984. The Natural History Museum identified the fish as flounder and smelt; there had been no reports of waterspouts in the Thames that night. And on 17 May 1996, a fall of more than 20 small fish was witnessed at Hatfield in Hertfordshire. Although they were dead, they seemed to be fresh and were warm to the touch.
9) Miss Annie Moberley, principal of St Hugh's, Oxford, and Miss Eleanor Jordain, a headmistress, were allegedly transported back to the 1790s while walking in Versailles on 10 August 1901, and met gardeners in green uniforms and tricorne hats. This time-slip or retrocognitive episode was immortalised in JW Dunne's book, An Adventure.
10) On 15 April 1912, the Titanic hit an iceberg and sank; in Morgan Robertson's 1898 novel Futility, the Titan sank on her maiden voyage after hitting an iceberg in about the same place. In 1939, the Titanian hit an iceberg in the place where the Titanic had sunk.
11) In the early hours of 27 May 1974, 20-year-old Barbara Forrest was raped and strangled at Erdington, near Birmingham. She had visited a friend the previous evening - Whit Monday - to get changed and had gone to a dance. In the early hours of 27 May 1817 (also a Whit Monday), Mary Ashford had been raped and murdered on the same spot. She too had gone to a friend's house to get changed before going to a dance. In both cases, a man called Thornton was arrested, charged with murder and cleared.
12) On 28 August 1974, ex-Prime Minister Edward Heath helped to publicise a novel by John Dyson called The Prime Minister's Boat is Missing. Five days later, Heath's yacht, Morning Cloud III, was lost.
13) In 1935, Mrs Gertrude Smith of York, Pennsylvania, discovered that she could mentally coax her hens to lay eggs bearing images, such as sunflower petals or her initials. There were many witnesses. When she visualised an egg whose cross-section would look triangular, and one arrived, she grew afraid and gave it up.
14) On the night of 1 July 1951, Mary Reeser, of St Petersburg, Florida, was reduced to ashes. Her chair was burnt, but a pile of papers beside it was untouched. In September 1967, the body of a tramp called Bailey was found in a derelict house in Lambeth, London. A blue flame was "issuing at force" from a slit in his stomach. No hypothesis adequately explains all the observed phenomena of SHC (spontaneous human combustion). The orthodox theory - that burning clothes boil off body water, absorb melted fat and then act as a wick around the body, reducing it to a pile of ashes - has never been demonstrated on a human body without an accelerant. Most puzzling, perhaps, are those cases without a visible source of ignition. Explanations in terms of electrostatics and geomagnetism remain highly speculative.
15) On 8 July 1947, a fortnight after Kenneth Arnold's "flying saucer" sighting (see item 4), a USAF press release from Roswell, New Mexico, announced the retrieval of "a [flying] disk", a report denied later the same day when the Air Force told reporters that the "disk" was nothing more than a weather balloon. The supposed "saucer crash" and retrieval of alien bodies have since become famous as the start of an alleged US government cover-up; but the incident is based entirely on wildly contradictory anecdotes collected more than 30 years later. The USAF changed its story in 1994, saying that the Roswell debris came from a top-secret Project Mogul radar balloon used for spying on the USSR. They also subsequently made a staggeringly inept attempt to discredit the "alien bodies" farrago by suggesting that witnesses were remembering experiments with anthropomorphic dummies jettisoned from aircraft; but these tests occurred between 1954 and 1959, not in 1947. Further fuel for conspiracy buffs was provided recently when the General Accounting Office, the Government watchdog agency, found that administrative records at Roswell from March 1945 to December 1949, and its outgoing messages from October 1946 to December 1949, had been destroyed more than 40 years ago.
16) Roy Cleveland Sullivan was born in 1912. During his 36 years as a park ranger, Sullivan, of Waynesboro, Virginia, was struck by lightning seven times. In 1942, he lost a big toenail to lightning. In 1969, his eyebrows were blown off. His left shoulder was seared in 1970 and his hair set on fire in 1972. In August 1973, he was out driving when a bolt hit him on the head through his hat, set his hair on fire again, threw him 10ft out of his car and knocked his left shoe off. In 1983, he shot himself.
17) Unexplained disappearances of famous people have given rise to a whole industry of speculation. Key vanishings of the century include the Labour MP Victor Grayson, who vanished during a train journey from Liverpool to Hull in 1920; Colonel Percy Fawcett, last seen embarking for the Amazon jungle in 1925; Glenn Miller, the jazz star who disappeared during a flight over the English Channel in 1944; and, of course, Lord Lucan (1974). But the oddest case of all was that of Ambrose Bierce, the American satirist who wrote about mysterious vanishings. He went to Mexico in 1913 and was never heard of again. (He was variously reported to have been killed fighting for or against Pancho Villa, neither being very likely, as he was over 70 and an invalid when he disappeared.
18) On 2 April 1968, the Virgin Mary began to appear on the roof of the Coptic church in the Cairo suburb of Zaitoun. The visions continued well into 1971 and it is thought that more than a million people witnessed the luminous tableaux. The still photographs are all fuzzy and ambiguous (the best is shown, far right, on the opposite page); and no film footage was made.
19) In February 1995, a plaster statue of the Blessed Virgin Mary in the Italian port of Civitavecchia allegedly started to weep dark red tears, attracting thousands of pilgrims. By 14 April, Good Friday, the statue was said to have wept 14 times. In the subsequent two months, there were up to 15 similar cases across Italy; it was like the moving statue mania that swept across Ireland in 1985. A laboratory report concluded that the liquid coming from the Virgin of Civitavecchia was male human blood. The Gregori family, who had obtained the statue from Medjugorje, were suspected of fraud, but refused to give blood for DNA tests. The Vatican subsequently declared the tears to be "genuine", but stopped short of declaring it a miracle.
20) One blustery night in 1917, Ester Hallio and another Finnish student, alone in a house in Helsinki, heard a clicking noise, and found two large overcoat buttons on the parquet floor. These were followed by falling coins every few minutes. Neighbours were brought in to witness further falls. These included Professor Arvi Grotenfeldt, a member of the Society of Sciences, who compiled a report of the incident. More than 10 marks was collected. Other unexplained falls of metallic objects have been reported at: Wellington, New Zealand, in March 1963 (pennies and stones bombarded a lodging house - ultimately watched by 600 people - for three days); Ramsgate, Kent, in 1968 (40 to 50 pennies in 15 minutes); and Galax, Virginia on 12 to 14 July 1978 (400 nails in three days).
21) John and Christine Swain from Somerset, driving through back lanes in the New Forest, Hampshire, with their two sons in 1952, came upon a mist-enshrouded lake near Beaulieu Abbey. Fifty yards out, there was a boulder with a sword in it, which the family took to be a memorial to King Arthur. About once every three weeks for the subsequent 17 years, the Swains drove to the New Forest, in the hope of finding the lake again - but without success.
22) On 8 September 1987, Minnie Clyde Winston, 77, stepped out of her bath at 1114 Fountain Drive, Atlanta, Georgia, to find the floor oozing blood "like a sprinkler". She and her husband William, 79, didn't have any pets and the house was free from vermin. The following morning the Winstons called the police, who found "copious amounts of blood" spattered on walls and floors in five rooms. The house was declared a crime scene to keep the press and public at bay. The State Crime Lab revealed the blood was human, type O; both Mr and Mrs Winston were type A. The police left and one presumes the case is still on file as "unsolved". Another house dripped blood in Saint Quentin, Picardy, in January 1986; while in August and September 1919 the ceilings of the rectory in Swanton Novers, Norfolk, seeped petrol, paraffin, sandalwood oil and methylated spirits. Walls of the rectory were torn open and ceilings exposed, but the mystery wasn't solved. One report said 50 gallons of the substances had been collected.
23) On 5 November 1975, a forestry worker called Travis Walton saw a light in woods near Snowflake, Arizona, while driving with five friends. He walked towards it, and was felled by a flash. Terrified, the others drove away. A big search failed to locate Walton; but five days later he turned up in nearby Heber, with a detailed account of abduction by aliens in a flying saucer; he passed a lie-detector test.
24) In October 1930, about 40 cars stalled simultaneously and could not be restarted for almost an hour on a road in Saxony. The subject of secret rays that could stop machines had been enthusiastically discussed in the popular press in 1923-24. Harry Grindell-Matthews, the eccentric British genius, even claimed to have invented a ray machine. The Second World War was rife with rumours of machine-disabling devices, and since then the stalling of car engines has often figured in narratives of UFO close encounters.
25) On 5 June 1932, Svanhild Hansen, aged four, was playing in the Norwegian village of Leka, near Trondheim, when a huge eagle grabbed her and carried her for more than a mile before dropping her on a high ledge. Villagers found her asleep and unharmed apart from scratches.
26) Two photographs of crypto-zoological entities have achieved iconic status: the 1934 "surgeon's photograph" of the Loch Ness Monster and Eric Shipton's 1951 photograph of an Abominable Snowman footprint in the Himalayas. Dr Kenneth Wilson, a London gynaecologist, took the Nessie photo, which was published in the Daily Mail on 21 April 1934. Fifty-nine years later, a man called Christian Spurling claimed on his death-bed that he had taken part in hoaxing this photo, using a model made from plastic wood; but not everyone is convinced, and the debate continues. As for the Abominable Snowman, there are inconsistencies in Shipton's accounts of how his photo was taken - and it's true he was fond of practical jokes.
27) In October 1967, Roger Patterson filmed what appears to be a Bigfoot at Bluff Cove, California. No one has proved the footage is fake, but sceptics naturally maintain it is a big bloke in a gorilla suit.
28) Between 16 June and 5 July 1945, there were 400 mysterious conflagrations in the region of Almeira in Spain. People dressed in white frequently caught fire while out in the open; laundry laid out to dry under the sun burst into flame, and white-painted walls were singed. Scientists suggested some unknown form of static discharge.
29) In 1986, clothes, furniture, carpets and electrical equipment burst into flames in the presence of Sascha K, a 13-year-old schoolboy from the Ukraine's Donetsk basin. Objects flew about, lightbulbs exploded, and a fridge turned upside down. Sascha was brought to a Moscow hospital and examined by the chief physician, Victor Korchenko. "While he was in the hospital," said Korchenko, "the clothing of a boy who shared a room with Sascha caught fire". One witness said a shoe flew off his foot and out of a window when Sascha walked into the room.
30) Ernest Jellett was walking through woodland near the Heathy Park Reservoir, Surrey, on 16 July 1962, when a big cat chased a rabbit towards him. It was the first of many local sightings of the "Surrey Puma". Throughout the Nineties, I have prepared annual surveys of ABC (Alien Big Cat) sightings, which are one of the most frequent brushes with the unknown in Britain. There are hundreds of sightings from at least 30 counties every year.
31) In 1966, a "saucer nest" - a circular area of flattened vegetation - was photographed in Tully, Australia. A series of such "nests" prefigured the British crop circle phenomenon that took off quietly in the late Seventies and grew into a major school of landscape art, reaching its zenith of publicity in 1991 with the Alton Barnes crop glyph, which featured on a Led Zeppelin album cover. Dispassionate observers regard the majority as man-made, but there's always an outside chance of something more mysterious. That's part of the fun of studying strange phenomena.
32) For the past 20 years, cattle mutilation has been the subject of much speculation among ranchers and conspiracy buffs in America. The bizarre nature of hundreds of these incidents - such as the draining of blood, apparent surgical incisions, missing organs, associated UFO sightings and lack of footprints - has spawned several distinct and whacky scenarios involving satanic cults, secret government experiments and research by extraterrestrial "scientists". Perhaps the most extreme variation was a scare across Spanish-speaking America in 1996 about a protean predator called "Chupacabras" or the "Goatsucker". This bugbear was blamed for killing and draining the blood from hundreds of goats, chickens, dogs, cows and other livestock, often leaving a single puncture mark. Witnesses described a fanged, kangaroo-like entity with bulging red eyes; or, later, a humanoid, cloven-hoofed predator with spines down its back. Some spoke of a smell of sulphur.
33) One of the highlights of the American SETI (Search for Extraterrestrial Intelligence) programme occurred at 10.16pm on 15 August 1977, when the radio telescope at Ohio State University picked up a 37-second signal from the direction of Sagittarius, far stronger than anything ever picked up before. When a researcher came across the signal on a computer printout, he scribbled "Wow!" in the margin. According to Robert Dixon, head of SETI, "It wasn't a spacecraft or an echo from a satellite. It was unmistakably of intelligent origin and had all the hallmarks of coming from an intelligent civilisation." The transmission, known today as 6EQUJ5 or the "Wow signal", was way off the scale of any previous - or subsequent - signals.
34) An ITN news bulletin broadcast by Southern Television on 26 November 1977 was interrupted by the slow, deep voice of "Asteron from the Intergalactic Mission", accompanied by an eerie booming sound. "All your weapons of evil must be destroyed," it said. "You only have a short time to learn to live together in peace... or leave the galaxy." Presumably a prank, although no one was ever caught.
35) On 31 August 1977, a chest of drawers slid along the floor of a Mrs Harper's council house in Enfield, west London. Her neighbours heard noises, and the police saw furniture skidding around. Psychic researchers and Fleet Street reporters also witnessed poltergeist activity, including levitation, which lasted until October. Despite some evidence that the Harper children made some of it up, there were enough unexplained phenomena to make this one of the most celebrated poltergeist cases of recent years.
36) In March 1978, Ukrainian crane driver Yuliya Vorobyeva received a 398-volt shock and was declared dead. She recovered two days later during her autopsy, was sleepless for six months, then slept. When she awoke, she claimed that she could see through people, and was employed at Donetsk hospital to diagnose rare illnesses. She impressed a doctor by telling him that his hearing was better in one ear and his right eye was weaker than his left. She correctly told an Izvestia reporter that he had eaten "kisel", a kind of red starchy jelly.
37) On 13 July 1980, children gathered for a junior brass and marching band competition at the Hollinwell Show near Kirkby-in-Ashfield, Nottinghamshire. More than 200 children and some adults collapsed and were ferried to hospitals. Symptoms included fainting, running eyes, sore throats, dizziness, vomiting, trembling, weakness, numbness, and a metallic taste in the mouth. It wasn't food poisoning, crop sprays, high-frequency radio waves, or a mystery bug. It was eventually put down to mass hysteria, or the more politically correct "mass sociogenic illness", the precise cause of which is unknown.
38) On 18 October 1984, an irregularly-shaped hole, about 10ft by 7ft and 2ft deep, was found on a remote farm near Grand Coulee, Washington State. A large plug of earth, the same size and shape as the hole, rested on the ground 75ft away. Between plug and hole were "dribblings" of stones and earth, but there was no sign that the plug had been dug out with machinery, or dragged or rolled to its new position. A meteor was ruled out, as the hole was not a crater but had vertical walls and a flat bottom. A whirlwind might have had enough suction, but could not have performed the operation with such neatness.
39) Mystery humming can be heard in various places round the world, but not everyone can hear it. The most famous hum in America started annoying residents in Taos, New Mexico, in 1991 and was the subject of intense study including a Federal investigation. In 1994, the University of New Mexico surveyed 8,000 residents; of 1,440 respondents, 161 (11 per cent) reported hearing the hum. Tinnitus was ruled out.
40) Isidor Fink, a laundry proprietor, was found dead with bullet wounds in a room locked from the inside in East 132nd Street, New York, on 9 March 1929. Screams and blows had been heard, but no shots. Nothing had been stolen.
41) Cancer victim Gloria Ramirez was rushed to Riverside General Hospital near Los Angeles on 19 February 1994. Shortly before she suffered a fatal heart attack, a blood sample was taken which appeared to contain white particles; staff reported an ammonia-like smell, and an oily sheen was noticed on the patient's body. Six workers passed out and many more suffered headaches, dizziness and nausea. Two were in intensive care for weeks with breathing problems and muscular spasms. Blood tests suggested organophosphate (pesticide) poisoning, but no trace of such a chemical could be found either in Ramirez's body or in the emergency room. At first, the health authorities diagnosed "mass sociogenic illness", but then a lab report suggested that Ramirez had used a skin cream containing DMSO (dimethyl sulphoxide), which, by an unprecedented chemical reaction, had broken down to form dimythyl sulphate, a chemical warfare agent.
42) The Second World War saw the oddest case of Foreign Accent Syndrome on record. A Norwegian woman, hit on the head with shrapnel during a German air raid on her village, fell into a coma and woke up with a German accent, as a result of which she was ostracised by her neighbours.
43) In November 1960, several witnesses saw a phantom army on a road near Otterburn, Northumberland, the site of a 14th-century battle.
44) Farmer Heino Seppi was collecting cut timber from the woods of Yrijo Kanto in the Palloneva region of western Finland in October 1969. Splitting an aspen log, he found its middle rotten, forming a hollow that contained a dried fish about 40cm long, resembling a perch. There was no clue as to how the fish got there.
45) Mrs Dilys Cant failed repeatedly to back her car into a vacant space in a car park in Durham in 1975. It felt as if she was hitting a kerb, although nothing was visible. Her daughter and two other motorists were also unable to enter the space, which seemed to be protected by "an invisible force field".
46) Edwin Robinson suffered a severe head injury in a 1971 road accident and gradually lost his sight and hearing. On 4 June 1980, he was struck by lightning outside his house in a suburb of Portland, Maine. He survived, because of his rubber-soled shoes, but remained unconscious for 20 minutes. On regaining consciousness, he found that his central vision was back and that he could hear perfectly well without his hearing aid (which had been burnt out by the lightning).
47) In September 1985, the Chinese press reported a discovery on a strip of land, 1km by 15 metres, in Huanre county, Liaoning province. In winter, when the temperature drops to -30C, the strip remained at 17C; in summer, the strip froze to a depth of one metre. The locals used it as a fridge in summer and for growing vegetables in winter.
48) In 1943, the USS Eldridge, berthed at the Philadelphia Naval Yard, disappeared for a few minutes as a result of a radar-evasion experiment, after which members of the crew suffered from sporadic invisibility, madness, and spontaneous combustion - or so the story goes. The US Navy denies that the experiment ever took place, and indeed the evidence for this intriguing adventure seems to be so much moonshine.
49) We had originally intended to include a 50th item, about the Bermuda Triangle, but it has disappeared.