Galeras, Columbia
Located within the walls of the southern part of Columbia right by neighboring Ecuador, this giant of a volcano has been active for more than a million years. 1580 was its first documented eruption. Danger levels escalate because of the fact that the city of Pasto is in one of its sides. Pasto has 450,000 residents and an explosion would bring in huge fatalities. 1993 saw an explosion that killed 9 including 6 volcanic scientists.
