Andy Rouse / Mountain gorilla (Gorilla beringei beringei) silverback male portrait, Volcanoes NP, Virunga Mountains, Rwanda

Pedro Narra / Mountain Gorilla (Goriila beringei) resting, Volcanoes National Park, Virunga Mountains, Rwanda.

Vincent Grafhorst / Man looking into crater at night, Mount Nyiragongo, Virunga National Park, Democratic Republic of the Congo

Vincent Grafhorst / Lava in volcanic crater, Mount Nyiragongo, Virunga National Park, Democratic Republic of the Congo

Christophe Courteau / Lava Lake at night in the crater of Nyiragongo Volcano, Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Christophe Courteau / Lava Lake at night in the crater of Nyiragongo Volcano, Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Christophe Courteau / Steam rising from the crater of Nyiragongo Volcano. Virunga National Park, North Kivu Province, Democratic Republic of Congo. September 2015.

Andy Rouse / Mountain gorilla (Gorilla beringei beringei) mother with young, and silverback in background. Virunga Mountains, Rwanda. Non-ex.

Andy Rouse / Mountain gorilla (Gorilla beringei beringei) portrait of blackback male, Virunga Mountains, Rwanda

Cyril Ruoso / Mountain Gorilla (Gorilla gorilla beringei) large silverback continuing to display after attacking a tourist, Virunga Mountains, Rwanda

Andy Rouse / Virunga Volcanoes National Park at dawn. Rwanda, Africa, April 2010.

Andy Rouse / Harvested potatoes in Virunga Volcanoes National Park with agricultural land behind and forest beyond where the mountain gorillas live, Rwanda, April 2010. Encroachment of the human population on habi...