A massive volcanic eruption that occurred 73,000 years ago killed off much of India's forests and may have pushed humans to the brink of extinction, a new study says. The Toba eruption, which took place on the Indonesian island of Sumatra, sent so much ash into the air that sunlight was blocked for six years.

Have you been noticing unusually beautiful sunsets over the past few weeks? Blame it on a volcanic eruption that happened June 12, half-a-world away. After Russia's Sarychev Peak volcano blew its top, it sent massive plumes of sulfur dioxide into the air and the gas has been circling the globe.

Mount Galeras in Colombia erupts, covering a nearby city in ash and forcing 7,000 people to evacuate their homes. The 14,110-foot volcano, which is considered Colombia's most active, last exploded in January 2008.