Mexico’s Popocatepetl volcano most recently became active again in 1994 and has been frequently erupting. Due to the emitted heat, the last glacier melted away in 2001. It is especially dangerous due to the huge populace just 70 kilometers (43.5 miles) away – a total of 20 million people in Mexico City.
Located in the center of Indonesia, the Merapi volcano is the most active in the country. Since the 16th century, it has been erupting almost continuously, with the most recent eruption occurring in 2018. The 3 million inhabitants of the surrounding area are alert to the situation at all times as Merapi is known for pyroclastic flows that rush down its slopes at alarming speeds.
This quite active volcano destroyed large parts of the archipelago of Krakatoa in 1883, releasing 13,000 times the energy the atomic bomb of Hiroshima had. In the 1920s, the volcano created the island of Anak Krakatau, growing each year by approximately 7 meters (23 feet). The situation worsened in 1994, progressing to an even more severe eruptive phase in 2007, with the most recent warning sounded in 2017.