One of the most fascinating treks in Laos is to Dong Phu Vieng NPA (ປ່າສະຫງວນແຫ່ງຊາດດົງພູວຽງ), which offers a rare chance to step into a rapidly disappearing world. The park, south of Muang Phin in the centre of Savannakhet Province, is home to a number of Katang villages, where you can stay if you observe local customs.
The trek involves a fair bit of walking through a mix of forests ranging from dense woodlands to bamboo forests and rocky areas with little cover, or paths only accessible during the dry season (November to May). There's a boat trip on the third day. A village guide leads trekkers through a sacred forest where you'll see lak la'puep (clan posts placed in the jungle by village families). Animals regularly seen include the rare silver langur, the leaf monkey and the hornbill.