Plumbing and travel rarely intersect happily. Pipes and cisterns are usually of interest to holidaymakers only when, in a cheap hotel or aboard an expensive cruise, they go wrong – often in an alarming and inconvenient manner. But in a dramatic fortress high above Israel's Negev Desert, the plumbing system is the climax of an extraordinary location.
In this part of the Holy Land, "high up" is a relative term. Masada stands 1,000ft above the surrounding land, but this base happens to be the deepest valley on Earth. The ascent to the top begins close to the shore of the Dead Sea, which is the lowest dry land in the world – almost a quarter-mile below the level of the live Mediterranean, two hours away across the mountains. Masada soars above the shimmer of hypersalinity, atop a thrust of rock that is a perch fit for a king.
King Herod – the monarch who, besides building the Second Temple in Jerusalem, slaughtered foes and family – was first attracted here by Masada's apparent impregnability. During a power struggle around 40BC, according to Flavius Josephus's account in The Antiquities of the Jews, he "placed his mother Cypros, and his sister, and the whole family at Masada" with a force of 800 men to guard them. After he had taken power in Judaea with the backing of the Romans, he decided he needed a refuge – the equivalent of a nuclear bunker for a 21st-century ruler.
Masada, which began life as a Bronze Age camp, was the place. From below it appears like a cliff that has come adrift from its neighbours; from above it resembles a ragged diamond. And just below its northern tip is Herod's most desirable residence: a palace-villa on three levels accessible by a secret staircase, a hideaway within a hideaway. Such splendid isolation would be ruled hopelessly uneconomic and impractical by 21st-century builders, but labour was both cheap and expendable.
Today, thousands of tourists are drawn by what the king of the Jews created. The energy requirement has lessened a little since 1998, when a cable car has been strung inelegantly from close to (Dead) sea level to near the fortress entrance, from which you can study the steep pathway that forms a hieroglyphic on the mountainside, and more particularly the mad dogs and Englishmen hauling themselves up the mountain like a noonday mirage.
But the inconvenient location means that everyone tends to show up all at once, pretty much on the stroke of noon. Anywhere else in the world that might be an irritation; here, in the natural cauldron that is the Jordan Valley, the heavens deploy a torment of biblical proportions. Which translates as lots of wilting tourists snaking around ruins where the near-vertical sun makes even meagre shade elusive for visitors. Only the most compelling location could make such suffering worthwhile. And Masada is worth the while it takes to get there, and the stamina you need to stay there.
The rewards begin with the views, which alone would justify the climb. The eye can scarcely comprehend the scorched magnificence of the Jordan basin, which is the finest, most profound creation along the Rift Valley. To the west, a wide-screen wasteland. A desert of crumpled khaki, stained by the occasional scraggy attempt at foliage, rises to a jagged horizon. To the east, you sense how a camera's automatic viewfinder feels without a point to focus upon: the heat haze ripples towards a smudge on the horizon that comprises the mountains of Jordan.
The plateau itself bears the decaying fruits of several epochs. Herod's domestic demands required formidable infrastructure in terms of storehouses and garrisons. The synagogue is said to be the oldest Jewish house of prayer in the world. After Herod's death the palace fell to the Romans, who installed the statutory bath-houses, and much later a Byzantine church was built. (Some patches of the original frescoes survive.) The most dramatic chapter in the Masada story, though, occurred after the Zealots (first-century guerrillas, fighting against Roman rule) took over Masada. They found not only refuge, but also a stockpile of provisions dating from Herod's time: "Here had been stored a mass of corn, amply sufficient to last for years, abundance of wine and oil, besides every variety of pulse and piles of dates," wrote Josephus.
Under their leader Eleazar, the 700 Zealots waited for the Romans to come. When they did, they set about purposefully to demonstrate that even Masada could be breached. The "Roman Ramp" may sound like an accessible route to the Colosseum; in Masada, it is a massive earthwork constructed to wage war. They used wood, stone and earth to construct a platform reaching up to the walls.
The oft-repeated story goes that, the evening before the final assault, Eleazar gathered his men and persuaded them to kill their families and themselves before the Romans could breach the defences. They would leave their weapons and their food as proof that they were not defeated by the besieging force.
Next morning the Romans – according to Josephus – found only a couple of women and a handful of children who had hidden in a cistern while the slaughter took place. While many historians have cast doubt upon his version of events, the story remains an important element of Jewish history – and the ramp still testifies to the attack.
The plumbing system was an even more impressive piece of engineering. How could everyone from the royal residents to the lowliest slave be kept alive when the only water source was 10 times as salty as the sea? A few times each year, the corrugation of cliffs to the west would enjoy a brief downpour. The engineers calculated that the run-off could be channelled into culverts around the mountain, and then into giant cisterns. These were duly hewn. Even today these man-made caves astonish, eight of them in sizes up to that of an aircraft hangar. They sustained the high life in the most inhospitable desert.
From ancient plumbing triumphs, to modern plumbing disasters: the Dead Sea. When Herod took the waters two millennia ago, by the time the Jordan River arrives to replenish the lake, it has dwindled to almost nothing, its waters diverted upstream for irrigation. Since 1970, the surface has dropped by an average of an inch per fortnight. Some of the earlier hotels built on its shores now stand forlorn on a dry-roasted former sea bed a quarter-mile from the water.
South of Masada, a more modern cluster of hotels offers the float-effortlessly-while-I-read-the-paper Dead Sea experience. Choose your own oasis of modernity, borrow a towel, wince as you tiptoe over the scorched earth, and immerse yourself in weightlessness.
Whatever your body mass, the concentration of minerals will support you (and, if you believe the hype, restore you) as you drift with unholy ease around this corner of the Holy Land. Careful how you go: swimming as practised in the local baths, where the worst that can afflict you is a splash of chlorine, is unwise: the hyper-buoyancy does strange things to your aquatic posture, which can tip up unexpectedly. Swallowing even a spoonful of the stuff will put you off salt for weeks. And a bead or two of Dead Sea water in an eye stings bitterly.
Thankfully, the miracle of modern plumbing allows you to sluice it clean with fresh water, and wash off the saline drips before they solidify and you turn into a pillar of salt. After a day of adventures in this strange super-heated, hypersaline world, you could feel more relaxed than ever.
The current advice from the Foreign Office to British travellers echoes Herod's concerns: "Maintain a high level of vigilance." But as the sun finally slips behind the cliffs of Judaea, the cares of the world seem to fade with the light.
Travel essentials: Masada and the Dead Sea
The low down
* The main gateway is Tel Aviv, served by British Airways (0844 493 0787; ba.com) and El Al (020-7121 1400; elal.com) from Heathrow; by easyJet (0905 821 0905; easyjet.com) and El Al from Luton; and by Jet2 (0871 226 1737; jet2.com) from Manchester.
Schedules, and onward travel possibilities, are affected by the Jewish Shabbat from sunset Friday until sunset Saturday.
A train runs from the airport to Tel Aviv Central railway station, from which bus 480 serves Masada. An alternative bus, 405, runs from Tel Aviv's main bus station.
* Masada (00 372 8 658 4207; parks.org.il) opens 8am-5pm daily (to 4pm on Fridays) between now and September, closing an hour earlier from October to March.
The cable car costs NIS27 (£4.50) single, NIS45 (£7.50) return. Admission to the National Park is an additional NIS27 (£4.50).
* Longwood Holidays (0844 770 4877; longwoodholidays.co.uk) is a long-established operator to Israel, as is the El Al subsidiary, Superstar Holidays (020-7121 1500; superstar.co.uk).
* The most appealing forthcoming specialist trip is a 10-day Israel and Palestine itinerary from Martin Randall Travel (020-8742 3355; martinrandall.com), departing 16 October. The price of £3,660 per person (based on two sharing) includes flights from Heathrow on El Al, mostly five-star accommodation with breakfast, five lunches and seven dinners, transport, guiding, admission fees and tips.
* Among the numerous hotels lining the shores of the Dead Sea south of Masada, the Lot Spa Hotel at Ein Bokek (00 972 8 668 9200; lothotel.co.il) is recommended for good facilities and service. A night in a double room with half board costs US$325 (£217) per night.
* The Foreign Office says: "There is a general threat from terrorism; attacks cannot be ruled out and could be indiscriminate, including in places frequented by expatriates and foreign travellers."
* British citizens visiting Israel as tourists do not need visas. "Expect lengthy personal questioning and baggage searches by security officials on arrival and departure," says the Foreign Office.
The presence of an Israeli passport stamp in your passport can cause problems when travelling to other countries in the region; immigration officials may agree to stamp a card rather than your passport, but this courtesy cannot always be relied upon.
* The Holy Land: an Oxford Archaeological Guide (5th edition, £18.99) by Jerome Murphy-O'Connor makes a wise companion.
* Flavius Josephus's works on the history of the Jews are widely available on the internet, for example here: bit.ly/MasadaMan. * Among the many good guidebooks, the Bradt Guide to Israel (£15.99) by Samantha Wilson is well written and useful.
The shore of the Dead Sea is currently 1,378ft below sea level, making it easily the lowest point of dry land on the planet. The lowest point in California's Death Valley, pictured above, is a mere 282ft; the Fens of Cambridgeshire go no lower than 13ft. The lowest capital in the world is Georgetown, Guyana, which sits around seven feet below sea level.
The lake itself is shrinking; between 1930 and 1999 the water level fell 80ft, partly due to geological shifts. Beneath the surface, the Dead Sea is 1,083ft at its deepest. The lowest road in the world runs alongside the Dead Sea, on the Israeli side and the hotels on either shore are also the lowest on Earth.
The world's lowest airport is Masada (code MTZ), at 1,240ft below sea level. Pilots must adopt special procedures to take off and land, because of the reluctance of their flight instruments to recognise altitudes lower than zero.
One superlative that the Dead Sea cannot claim is the world's saltiest body of water; at around 30 per cent salinity, it is exceeded by Lake Assal in Djibouti (about 35 per cent) and Don Juan Pond in Antarctica (40 per cent). The Mediterranean is around 3.5 per cent.