On 15 September 2004 the eye of a giant storm passed over a set of scientific gauges on the seabed of the Gulf of Mexico. The instruments measured the size of the waves created by Hurricane Ivan as it headed towards the American coast.
A study published today in the journal Science reveals that the hurricane created waves measuring at least 90 feet (30m) from crest to trough - the tallest and most extreme open-ocean waves ever recorded by modern instruments.
By monitoring differences in water pressure on the seabed, the scientists were able to estimate the size of the column of water overhead.
The findings demonstrate that scientists have in the past underestimated the size of the waves that can be generated by hurricanes, said William Teague from the Naval Research Laboratory in Stennis Space Centre, Mississippi.
The waves recorded were the size of a 10-storey building but were probably not the largest that the hurricane had generated, Dr Teague said.
He estimated that even bigger waves up to 132 feet tall were being created in other parts of the huge tropical cyclone.
Hurricane Ivan had already ripped through the island of Grenada when the seabed readings were taken, and went on to cause death and destruction on Jamaica, the Cayman island and finally the United States where it petered out.
The wave-measuring instruments on the seabed are shaped liked barnacles and are designed to help engineers build structures such as oil platforms that have to withstand extreme conditions.
The worst hurricane
Hurricane Mitch, which killed about 11,000 people in 1998, is considered to be the most destructive hurricane of modern times. Mitch struck Central America in October and November, destroying about 100,000 homes and leaving about 2.5 million people dependent on relief aid. Wind speeds reached 180mph for a 24-hour period, making it the strongest hurricane in the Caribbean in more than a decade.
Hurricanes normally last for between nine and 10 days and move westwards at a speed of about 12mph, gradually curving away from the equator as they move.
They are one of the most dramatic and destructive forces in nature. According to Bill McGuire, author of Surviving Armageddon and a natural hazards expert at University College London, the past 12 months have been the worst on record for hurricanes.
Five have struck Florida alone and the forecast for this year is that there will be about four times as many hurricanes as the annual average.
About 1.8 inches (4.6cm) of rain fell in a minute at Basse Terre in Guadeloupe on 26 November 1970 and 53 inches fell over a 12-hour period at Belouve on La Reunion island in the Indian Ocean.
The highest average annual rainfall - some 450 inches - is at Mt Waialeale in Hawaii. The highest recorded annual rainfall was 1,042 inches (nearly 87 feet) at Cherrapunji, India. It also recorded the highest rainfall in a calender month - 366 inches, or 30ft 6in.
Bombay last month recorded the highest rainfall in a single day in India - 37.1 inches.
Coldest place on Earth
The lowest recorded temperature outside a science laboratory was at the Russian research station at Vostok in Antarctica on 21 July 1983. It was minus 89.2C (minus 128.6F), cold enough to freeze your breath.
The temperature there is regularly between minus 30C and minus 60C, a result of the exceptionally high speed of the winds at this part of the frozen continent and the lack of solar radiation during the winter, when the days pass in complete darkness.
And while minus 89.2C is the official record, Vostok station reported, unofficially, that Vostok reached the temperature of minus 91C during the winter of 1997.
Hottest place on Earth
There are many contenders for this record. A weather station in El Azizia in Libya recorded 57.8C (136F) - hot enough to fry an egg - in 1922.
This record meets technical requirement in being made using a thermometer 5 feet above the ground in an enclosed, shaded area.
Other locations have, however, almost certainly been hotter, but no formal record is available.
The Dallol Depression in Ethiopia, which is more than 100 meters below sea level, features yellow sulphur fields among the white salt beds. Temperatures can reach as high as 63C.
Another contender is Death Valley in California, which is also below sea level, where temperatures have been recorded as reaching 49C.
Wave of tornados
In April 1974, southern and mid-western US suffered its worst tornado episode. Over a 24-hour period, 148 swept through the region. Thirteen states from Alabama to Virginia were affected. After 16 hours, 330 people were dead and 5,484 were injured in a damage path covering more than 2,500 miles. Tornadoes form during thunder storms when warm, humid air collides with colder air to form a swirling vortex.
Driest place on Earth
The Atacama desert in northern Chile is the most arid tract of land known. On average the buff-coloured sands of this region receive less than 0.004in of rain a year. Some parts of the desert have not seen rainfall in 400 years; scientists see it as a good training ground for testing instruments to search for the presence of water on other planets.
The Atacama desert owes its conditions to the fact that it is sandwiched between the high mountains of the Andes on the east and the exceptionally cold currents of the Pacific Ocean in the west. Bodies buried there by prehistoric people are almost perfectly preserved as natural mummies.
The world's worst modern meteor strike
Early in the morning of 30 June 1908 a large and mysterious explosion occurred in the sky over eastern Siberia. Visitors to the site of the explosion at Tunguska in northern Russia saw catastrophic damage, with thousands of acres of forest felled.
Local reindeer herdsmen said they were blown off their feet during the impact. The fireball lit up the night sky for hundreds of miles around - some say that it could even be seen from London.
Scientists now believe the event was caused by a large meteorite breaking up as it entered the Earth's atmosphere. The lump of space rock exploded at an altitude of about 4 miles (6.4km), sending a huge pulse of explosive energy to the ground that flattened everything in its path.
The most destructive earthquakes
On 22 May 1960 an earthquake with a magnitude of 9.5 on the Richter scale struck off the coast of Chile. It is estimated to have accounted for about a quarter of the seismic energy released by all earthquakes in the past century. The US Geological Survey said that the earthquake killed 2,000 people, injured 3,000 and made another 2 million homeless. Tsunamis travelled across the Pacific, causing millions of pounds worth of damage in Hawaii, Japan, the west coast of the US and the Philippines.
However, the most destructive earthquake in modern times was in Tangshan, north-east of the Chinese capital of Beijing, in 1976. Officially the death toll was 242,419; unofficial estimates said 750,000.
The world's biggest volcanos
The most destructive volcanic eruption in modern times was that of Tambora on the Sumbawa island of Indonesia. It began on 5 April 1815 with a moderate explosion. Five days later "three columns of fire" rose into the sky and an estimated 50 cubic kilometres of molten magma were expelled. An estimated 92,000 died from the explosion or resulting starvation.
The debris thrown into the atmosphere caused global climate change. Crops failed as far away as America and many tens of thousands of people died from famine in the immediate vicinity of the eruption.Reuse content