The small Batok Volcano is located in Tengger Caldera, which is the 10 Km wide crater of a super volcano.
The Tengger Caldera is like a flat desert covered with soft volcanic ash, called Lautan Pasir (Sea of Sand). The caldera is surrounded by cliffs that are between 200m and 600m high, and can be accessed only by a couple of dirt-roads and foot trails.
The village of Cemoro Lawang is located across the Tengger Caldera from here (on top of the cliff, in the center-left of this photo), and the Bromo Volcano is behind the Batok Volcano.
For more information about the Bromo Tengger Semeru National Park, read en.wikipedia.org/wiki/Bromo_Tengger_Semeru_National_Park