Now regarded as little more than ruins atop a rock that offers a magnificent view, Sigiriya is undoubtedly one of ancient Asia’s Seven Great Wonders, albeit one that wears its wonders with clandestine dignity.

Its moment of destruction coincides most neatly with the date most historians give for the end of the ancient world itself – 500 CE. Just 5 years beforehand, the ancient world itself had come crashing to a bloody end around the base of this 1000-foot mountain in central Sri Lanka in 495 CE.

With it ended one of the most notorious parties the world had yet enjoyed, one that, at 22 years, totally outlasted even Cleopatra’s Feast. The party was Gatsbyesque in its exuberant excess. More opulent than the Rothschilds’ surrealist ball of 1972; more majestic than the Shah of Iran’s 2,500-year dynastic celebrations the year before, this party, like the ancient world itself, raced to its corporeal end with all the aplomb of the last serving of the previous martini on board the Titanic.

Of course, 500 CE is little more than a marker, a slender signal, a humble and iconic rounded-up figure that has been invented by historians eager to bring closure to the world of the Romans and Greeks, the Pharaohs, Assyrians, Hittites, Persians, or Han. But the date has stuck. Thereafter follows the medieval age, the early modern age. And the later early modern age; even the later modern age, and our own post-modern age, an age shorn of parties, or glamour, decadent or otherwise.

Sri Lanka’s 22-year end-of-history party followed exactly the dates of the reign of one of its most outrageous kings, an equatorial Nero with mesmeric hints, like the best of expensive wines, of other things - Vlad the Impaler; Nebuchadnezzar, Louis XIV. In joy, as Mark Twain observed, is sorrow, and Kashyapa, king, party giver, gourmand, and libertine, knew that his moment of doom was due to come sooner rather than later.

Gazing across the plains from his high fortress walls in Sigiriya, he would have been presciently aware that his brother would eventually arrive to stop all the fun. And so he did. Commanding a specially recruited mercenary army from nearby India, Moggallana had come to take back what he considered his by right – the throne.

The legitimate son of Dhatusena, one of the country’s most fabulous kings, as his heir, Moggallana would have looked forward to a reign of plenty after his father had chased the occupying Dravidian Tamils from the kingdom, and rebuilt the country, tank by tank, temple by temple. It was years of milk and honey (or Kittel) he had in mind – not penurious exile.

But it was not to be. His half-brother, Kashyapa, played family politics with the skill of a card shark. He outmanoeuvred his brother and, with the army commander's help, deposed his father, Dhatusena. Had things ended there, we may never have heard of Kashyapa. He would just have been yet another one of the island’s numerous coup d'état kings. But with Oedipian or Macbethian instincts, Kashyapa went further. Much further. He began by entombing his father alive in his palace walls. For so distinguished a king, to be reduced to mere bricks and mortar was a shocking way to end a reign.

And, to escape the widespread disapprobation this would have created, Kashyapa abandoned his capital of Anuradhapura in much the same way as Tiberius had abandoned Rome for Capri, and headed for Sigiriya. It's like, anywhere in Asia, was probably not seen again until the Kangxi Emperor built the Gardens of Perfect Brightness in the Old Summer Palace, outside Peking, some twelve hundred years later, in 1707. A capital for just one reign, Sigiriya was a cross between the Tivoli, Akhenaten’s Amarna, and the Brighton Pavilion. It enjoyed every last innovation and refinement available – and there were many.

The fortress itself sits atop a massive lump of granite - a hardened, much reduced magma plug – all that is left of an extinct volcano. Lost in forests, inhabited by hermit monks between the third century BCE and the first century CE, it was exposed by colossal landslides and then selected by Kashyapa as the location of a new fortress-capital in 477 CE.

Much of it is hard to identify today but, in its day, it set new standards for urban planning, the royal bastion surrounded by an elaborately laid out outer city, with a final circle of three types of gardens around it: water, terraced, and boulder gardens - 3 km in length and nearly 1 km in width, flanking its famous rock citadel.

Ponds, pavilions, fountains and cut pools made up the water gardens. More naturalistic gardens were created around massive boulders, creating an artless park with long, winding pathways to saunter down. Brick staircases and limestone steps led up to more formal terraced gardens.

Across it all stretch double moats and triple ramparts, defendable gateways, and steps in perfect geometric symmetry, locking all the elements of the fortress city together with mathematical precision and elegance and pierced by the massive sentinel sculpture of a crouching lion. The beast guards the staircase to the ancient palace six hundred feet above, though all that remains now are the two animal paws, rediscovered in excavations in 1898. Built with bricks and limestone, the lion’s full height was 45 feet. The rest of the creature lies in dust around the site, but even so, it gave its name to the place: “Sigiriya,” the Singhalese for “Lion’s Rock.” It is as if the walls of heaven itself defend it.

When Kashyapa died, having wisely chosen to drive a sword through his own body rather than be captured alive, the city sank into a desolate retreat for a handful of monks getting so overgrown by jungle through the passing centuries that its rediscovery in 1831 by Major Jonathan Forbes of the 78th (Highlanders) Regiment of Foot was the sensation of the year. Forbes was no ordinary officer. His book, Eleven Years in Ceylon, published in 1840, is regarded as a masterpiece. He himself was so obsessed with rumours of Sigiriya that he dedicated himself to detection, writing later: “From the spot where we halted, I could distinguish massive stone walls appearing through the trees near the base of the rock, and now felt convinced that this was the very place I was anxious to discover.”

Decades after the publication of Forbes’ book, the complete glory that underpinned Sigiriya was gradually revealed. Central to it all was its reliance on the world's most advanced water technology to power its fountains, lakes, wells, streams, and waterfalls. Rock-cut horizontal and vertical drains, underground terracotta pipes, tanks, ponds, interconnected conduits, cisterns, moats, and waterways channelled surface water to stop erosion. They tapped other water sources to deliver water to the huge ornamental gardens, the city and palace - and harness it to help cool the microclimate of the royal residences.

Exhibited here in Sigiriya are the most significant advances the country has made in developing technology and practices to harness the water that powers the state itself. Climbing to the top will not reveal them; indeed, most of it is still lost underground or in the forest. But it is there – traces of it, evident to the trained eye.

“There will,” stated Stephen King deferentially, “be water if God wills it.” But as any ancient Sri Lankan would have told him, this is only half the truth of the matter. Water, uncollected, undistributed, unpurified, is all but useless, however much ...