On Merapi's southern slopes is the village of KALIURANG , a tatty but popular hill station. A bus from Yogya's Umbulharjo station costs Rp700; it's Rp1000 by bemo from behind the Terban terminal on Jalan Simanjutak. In Kaliurang, you can join a trekking group to the summit, a fairly arduous five-hour scramble through snake- and spider-infested forest. During Merapi's dormant months, usually March to October, it is possible to climb all the way to the top, but at other times you may have to settle for a distant view from the observation platform. All treks begin at 3am, when the lava, spilling over the top and tracing a searing path down the mountainside, can be seen most clearly. Bring warm clothes, a torch and sturdy boots (against poisonous snakes). Treks cost Rp7500 including breakfast and are organized by Vogel's Hostel in Kaliurang, Jl Astya Mulya 76 (tel 0274/395208; under $5), which also happens to be one of the best budget hostels in Java. The owner is the head of the rescue team in Kaliurang.