A major tourist attraction of Laos, Wat Phou is an ancient Khmer religious complex. It stretches 1400m up to the lower slopes of the Phu Pasak range, also known as Phu Khuai or Mount Penis! The frangipanis that line the steps, the tumbledown pavilions, ornate Shiva-lingam sanctuary, and crocodile stone give it all a very mystical atmosphere. The site layout is unique to Khmer architecture and in 2001 UNESCO declaired it a World Heritage Site. There is a small but well kept and informative museum that is worth visiting on site and this sets the scene for Wat Phou, Angkor Wat and other Khmer sites in the region.
Many travellers skip Southern Laos because it's a bit hard to get to, but there are many gems to be found in Southern Laos!