Marum Volcano, Vanuatu
Credit: Grant Dixon / Getty Images

One of the most active volcanoes in the world, Marum is located on Vauatu's island of Ambrym. The volcano's bubbling lake of fire reaches more than 2,000 F and is surrounded by an ash plane rising out of lush rainforest. No one's more aware of the heat than photographer Geogg Mackley, who rappelled into the volcano in 2010. We recommend that you enjoy the view from outside the crater.