The Dieng plateau, an active caldera, is an area of intense and sometimes dangerous volcanic activity. Hydrogen sulfide gas, with its characteristic odor of rotten eggs, boils up from its many craters and fumaroles. Even walking on solid ground, one can hear the waters boiling beneath one's feet. The plateau's combination of misty remoteness, mountains, lakes, and volcanism probably awed the Sanjaya rulers and inspired them to build their temples in this impressive place.