Indonesia’s Mount Merapi Volcano

A lava dome is forming rapidly at the volcano’s peak. When it collapses, the most powerful stage of the eruption is expected to take place.  (Blontank Poer / Getty Images)

Its last eruption, in 1994, left 66 dead. Another in 1930 killed 1,300 people.  (Blontank Poer / Getty Images)

Mount Merapi spewed deadly clouds, known by locals as “wedhus gembelâ€� (shaggy goat) in May 2006. The clouds consist of gases, ash and dust that reach temperatures of up to 430 degrees Fahrenheit. A 1994 eruption left 66 dead. Another in 1930 killed 1,300 people.   (Blontank Poer / Getty Images)

Searing heat clouds belched out of the volcano early on Wednesday, May 17th, as scientists anxiously waited for a major eruption.  (Jewel Samad / AFP/Getty Images)

The alert remained at its highest level Wednesday for the 3,000-meter (9,800-foot) mountain at the heart of Java island. Scientists cautioned that a lull in activity did not mean the danger was over.  (Ed Wray / AP)