I arrived in Vientiane at the beginning of the year 2553, and within an hour I was soaked to the bones. It was the second day of Pi Mai Lao, the Buddhist New Year celebrations, when water fever grips the collective soul of Laos. The primary function of Pi Mai Lao is a display of reverence, and the temples along Thanon Settathirat were crowded with women dipping leaves into water pots and flicking the droplets over the statues of the Buddha.

Being the height of the hot season, it's hardly surprising that some of the water-play is less solemn. In fact, beyond the confines of the temples, the usual politeness that governs Lao society is mothballed and any aquatic torture goes during Pi Mai Lao - buckets, hoses or pump-action water pistols. A farang - a foreigner - alone, slightly dazed and foolish enough to wander around was a much-favoured target, and I ran a watery gauntlet racing from one temple to the next.

I took refuge in a cafe, but even the waitress was dribbling water on her customers. I felt a tap on my shoulder. It was my turn. "Nit-noy", she said - a little bit. I prepared my best-natured smile. A bucket of iced water crashed over my head.

Laos is, well, different. The flight from Bangkok to Vientiane, the capital, is an experience in time travel. On the east bank of the Mekong, Laos lies green and jungly, with dirt tracks instead of paved roads, bicycles instead of pick-up trucks - an untidy sprawl compared with the neat patchwork of rice fields on the Thai side of the river.

Laos is one of the last great recluse states of South-East Asia. Closed when the Communist Pathet Lao took control of the country in 1975, the country has only reluctantly unbolted its doors to travellers. For those who enter, Laos involves a paradigm shift. None of the normal precepts of tourism - that the plane will arrive on time, that the electricity in your room will work, that your guide will speak a recognisable brand of English - can be taken for granted. And yet poverty, socialism and preoccupation with its own troubles have distilled in Laos a version of the exotic Orient that has faded to a sepia-tinged reminiscence in other parts of South-East Asia.

Laos remains poignantly and stoically itself - a country of hill tribes and elephants and jungles filled with new species of twining plants waiting to be named.

Although Vientiane is almost unavoidable, the capital is one of the lesser glories of what was once Indo-China, redeemed only by its proximity to the Mekong. It once felt like the backdrop to a Graham Greene novel - crumbling, Frenchified and clandestine. These days, despite its lingering Gallicisms - baguettes, an affection for shuttered windows and the faint, stale whiff of Gauloises in the cafes - Vientiane leaves you with little more than a longing to be elsewhere.

After a half-day tour of the temples, a trip out to see the concrete statues at a Buddha theme park and a spirited ascent of the Pratuxai, the Lao version of the Arc de Triomphe, my guide shrugged his shoulders. "That's about it," he said, and with a sigh of relief from both of us we headed off to watch the sunset from one of the bars that jut out over the Mekong.

Most of the country's prime attractions lie in the north, and after an early morning bowl of rice porridge, I boarded a Russian helicopter and headed north across the sharp limestone peaks of northern Laos to Phonsavan, the capital of the Xieng Khuang province and gateway to the Plain of Jars. The region takes its name from the huge sandstone jars that lie scattered about the plain, some up to two metres tall and weighing several tons.

Who brought them or why is a complete mystery, although they were transported from hundreds of kilometres away between two and three thousand years ago. The jars themselves - anything up to 50 to a site - are awesome, tumbled about at various sites on the plain.

But it is not so much archaeology as war that dominates the Plain of Jars. Coming in to land, the scenery below looked like a giant golf course - comprehensively defoliated, with bomb craters for bunkers.

The reason for this devastation is its location. The Plain of Jars is the strategic key not only to northern Laos but also to the western highlands of Vietnam. In 1964, Pathet Lao troops and their North Vietnamese allies took the Plain and, in an effort to dislodge them, US bombers shattered the region in a saturation bombing campaign, and the detritus of war - bomb casings, perforated metal strips used for makeshift roads and aluminium fuselages from downed aircraft - now serve as fences, baths and pig pens.

Another dimension to the Plain of Jars is the H'mong people of the surrounding hills. The H'mong are among the most colourful of the hill tribes who make up the Lao ethnic soup. Staunchly independent, the H'mong migrated to Laos from southern China and form a vivid subculture, living in thatch villages, practising slash and burn agriculture, cultivating opium poppies and clinging to their animist beliefs. Traditionally minded female H'mong still wear their wealth in the form of silver jewellery, and embroidered black trousers and blouses give them the name "Black H'mong".

By far the most compelling sight of Laos is Luang Prabang. The former royal capital sits at the junction of the Mekong and the Nam Khan rivers in northern Laos, and it's easy to be seduced. The finger of land at the confluence of the two rivers bristles with temples which are surrounded by sacred bodhi trees and giant Buddha statues - an isthmus of holiness, administered by monks. On the corner opposite the Phousi Hotel is an encampment of hill tribe women, trussed in silver bangles and peddling colourful squares of embroidery.

A constant, colourful traffic of cargo vessels and garfish-thin passenger boats parades along the river, and in the background ranges of saw-toothed blue hills fade to pearl as they retreat toward China.

One of the great attractions of Laos is that there are so few "attractions". Laos has no Angkor Wat, and apart from the Luang Prabang, the Plain of Jars and a handful of temples, no compelling cultural treasures - which can be a great relief.

Anyone with great cultural expectations will quickly find themselves simmering around the hotel pool. The essence of Laos is to be found by wandering about, and for this Luang Prabang is perfect.

The only essential excursion from Luang Prabang is the boat trip upstream to Pak Ou Caves. The caves - deep cavities in the limestone hills that line the river - are crammed with thousands of Buddha statues that date back to the time even before Luang Phabang was founded.

Even for a devout Buddhist, an hour or so will exhaust all possibilities at Pak Ou. The real attraction is the puttering journey along the river - past fishermen casting nets, past hunched figures panning for gold, past water buffalo and palm trees and little villages of sticks and thatch where children dance along the bank like sprites.

It is a scene that has changed little since the first Lao princes came down the river from southern China.

I could almost have been a barging princeling myself, so loftily does Laos treat the foreigner on $400 per day. But just then one of the scimitar-nosed speedboats that ply the Mekong as far upstream as China came thundering past, lathering the river and drenching me in its batwing of shining spray, so that I left Laos as I entered - soaking.