Doi Inthanon is Thailand's highest mountain and its summit has the only true upper montane forest and sphagnum bog in the country. This granite massif with adjoining limestone outcrops is on the periphery of the mountaintop "islands" that stretch southeast from the Himalayas. Inthanon is a shortened name of the Chiang Mai Kingdom's last prince who gave importance to the mountain's watershed forests before he died in 1897. Typically shrouded in mist, the "fog-drip" caused by condensation on trees helps feed numerous tributaries of the country's major river system. Vachirathan Waterfalls has a single drop of 164 feet (50 metres), with a roar compared to stampeding elephants, while the even more impressive Mae Ya Waterfalls tumbles 820 feet (250 metres) down hundreds of small steps. In contrast, the cavernous Borijinda Cave is dotted with natural skylights, and serves as a peaceful meditation site for Buddhist monks. The lower and middle elevations of Doi Inthanon have suffered through shifting agriculture - some 4,000 hill tribe villagers live on its expansive slopes.