The most evocative Khmer ruin outside Cambodian borders, the World Heritage site of Wat Phou should be at the top of your southern Laos must-see list. A romantic and rambling complex of pre-Angkorian temples dating from the sixth to the twelfth centuries, Wat Phou occupies a setting of unparalleled beauty in a lush river valley. Unlike ancient Khmer sites of equal size or importance found in neighbouring Thailand, Wat Phou has yet to be over-enthusiastically restored, so walking among the half-buried pieces of sculpted sandstone gives a good idea of what these sites once looked like.

Wat Phou, which in Lao means "Mountain Monastery", is actually a series of ruined temples and shrines at the foot of Lingaparvata Mountain. Although the site is now associated with Theravada Buddhism, sandstone reliefs indicate that the ruins were once a Hindu place of worship. When viewed from the Mekong, it's clear why the site was chosen. A phallic stone outcropping is easily seen among the range's line of forested peaks: this would have made the site especially auspicious to worshippers of Shiva, a Hindu god often symbolized by a phallus.