THE FIRST THING I want to do when I get to the Tad Fane Resort in southern Laos is to look at the waterfall. Never mind that I can hear it from my cabin, its roar overpowering the midday screech of cicadas. Never mind that I can see the top of it from the restaurant. I want the full treatment: an uninterrupted view of twin torrents sluicing over a 120-metre cliff from jungle-clad plateau to rocky riverbed. Never mind that the mud path leading into the chasm descends a 45-degree slope. I persuade a resort guide to lead me down through the jungle, further and further, until we realise that what we are about to step on to is not solid land. It is simply thick foliage, with a few pinpricks of light winking a warning that it's time to give up. There's no sign of the bottom of the falls. Three hours and an upstream river crossing later, we're back at the top. A raging arch of water cascades over the edge then disappears into the chasm. Below us are sheer cliffs, curving round to form an enormous, open-sided cylinder. Their faces are a vivid green, soft and velvety with fresh foliage and shivering with tiny waterfalls behind a cloud of spray. The bottom is no more visible than before. But from here, we can see where we were standing earlier in the day. Patches of jungle slope down from the plateau to a sheer drop. A few steps more or a wrong footing on the mud, and we really would have seen the bottom. Tad Fane is at the edge of the Bolaven plateau, a volcanic slab that sheds water like a wrung sponge in the middle of southern Laos. The French once grew coffee here, and now the Lao do the same. Three friends join the guide and me on a four-hour hike later that afternoon and those coffee trees come in handy: we haul ourselves up by their sinuous branches. There are fig and guava trees, wild ginger plants with scented, red cone-shaped flowers, pomelos lying on the ground, and a strangler fig wrapped around the dead trunk of its former host. And there are leeches, hundreds of them, little brown monsters that stand on dripping leaves, waving as if in greeting, before attaching themselves to a passing leg. We stop at Tad Nyeung, a 40-metre cascade that drenches us with spray. On top of the falls, the water is surprisingly calm, and we jump in for a swim. I discover two leech bites on my foot, bleeding profusely. Our guide offers some leaves he's picked in the forest. 'This will stop the bleeding,' he says, as he applies the leaves to the bites; they dry up within seconds. Southern Laos is that kind of place: alive, wet, and filled with stunning beauty, sudden dangers, slight discomforts and overwhelming consolations. We arrive back at the resort in time to see a peach- and crimson-streaked sunset peeking through the forest that encloses the half circle of seven eco-friendly wooden cabins, then guzzle Beerlao and spring rolls and sit round the campfire in the surprising chill of the night air. It's time to move south. At Nakasang a long-tailed boat picks us up from a strip of stilt houses and rips out into the Mekong River. This is Siphandon, a 50km archipelago of 4,000 islands in the Mekong. After the brief adventure at Tad Fane, it is time to relax. Dense, formless jungle gives way to palm-fringed shores, then an odd sight emerges: a concrete arched railway bridge similar to those in provincial Europe. We alight in its shadow, on an island called Don Khone. There's no electricity supply on Don Khone, no cars and no phones. Just a few restaurants, some dollar-a-night cabins, a couple of nicer guesthouses and a row of old French buildings in varying states of repair. It is, however, home to one colonial oddity - the only railway line built in Laos. It ran for just 10km across Don Khone and over the bridge to the island of Don Det. The operation closed in 1945 after 30 years. After a day spent kayaking on the Mekong, my friends leave for Cambodia and reality bites. I discover, too late, that I have just US$40 to last six days. There are, of course, no credit-card facilities in southern Laos. It is time to be a backpacker again. I find out just what US$1 a night buys you on Don Khone: a bamboo cabin furnished with a bed, a mosquito net, cleanish sheets, an oil lamp and a hammock on a verandah over the Mekong. My hut is above a family bathing area, so at about 5pm each day, I watch a dozen or so children splash ecstatically in the brown water. My computer battery dies, my mobile phone has long since lost its signal and e-mail is a distant memory. I wash my T-shirts in a bucket, I read, I gorge on papaya and coconut milk, and I wander across Don Det. In the evening, I lie in the hammock as the river gurgles invisibly a few metres away. I haven't travelled like this since about 1987. It is bliss. And it has to come to an end. I climb into an open-sided minibus for a couple of hours and backtrack to Champasak, the provincial capital, past golden rice fields and pink-blossomed lotus ponds, to see Laos' greatest single monument: Wat Phou. A Khmer temple begun in the sixth century, Wat Phou was the beginning of the dream that would culminate, five centuries later, in the supreme achievement of Angkor Wat, across the border in Cambodia. It is on a far smaller scale than Angkor, but its stonework and placement - at the bottom of a powerful ridge extending from a mountain shaped like a lingam, a Hindu phallic symbol - are genius. An ancient path threads between large twin pavilions that have spent centuries shedding massive, exquisitely carved sandstone blocks that lie about in collapse. A steep staircase climbs through a lush corridor of frangipani trees, whose yellow and white flowers decorate the steps, towards the mountain. The view is of a tree-dotted, monsoon-green plain bounded by the Mekong, which curls across the horizon. At the top stands the holiest shrine of them all, now cracked almost in two but held together by the massive weight of its stonework, where a Shivalingam was once washed with water piped from a spring immediately behind it. The carvings on the lintels are as alive as the jungle around them. On one panel, what looks like a Shiva Natraj (one of the god's many incarnations) dances on top of a many-headed snake, joyfully celebrating the life-giving river. His eyes are closed and on his face is an expression of transcendental bliss; what looks like a wave gushes from his loins. Inside, the lingam has been replaced by a set of recent Buddhas with goofy smiles and elfin hats. I light an incense stick decorated with fresh marigolds before the Buddhas. I have US$7 left. It is time to leave. Pakse is the main staging point for the south. Lao Airlines flies from Vientiane daily, US$95 one way. A comfortable overnight bus service leaves Vientiane at 8.30pm and arrives in Pakse at 6am, US$18. Those with a Lao visa can cross the border from Thailand at Chong Mek, or from Cambodia at Veunkham. From Pakse, cheap minibuses and boats connect to all the above destinations. Accommodation: Tad Fane Resort, tel: [856 20] 530741; fax: [856 31] 212150; e-mail: reservations@tadfane.com , US$20 and US$30 a night. Sala Don Khone, tel: [865 31] 212725, e-mail: salalao@laonet -net; US$20 a night. In Champasak, try Souchitra Guesthouse, tel: [856 31] 213275, US$5 and US$10 a night. Wildside, a foreign-run agency, offers eco-tourism and adventure tours. PO Box 9099, Vientiane, Lao PDR, tel: [856 31] 251563, e-mail mick@wildside-laos.com ; www.wildside-laos.com