Mount Sabyinyo, Extinct volcano in the Virunga Mountains, Rwanda, DR Congo and Uganda

Mount Sabyinyo is an extinct volcano in the Virunga Mountains whose serrated summit, at 3,669 metres, marks the tripoint of the Democratic Republic of the Congo, Rwanda and Uganda. Its jagged profile, likened to worn teeth, contrasts with the conical peaks nearby, and its slopes lie within Virunga, Volcanoes and Mgahinga Gorilla national parks.

Mount Sabyinyo is the oldest volcano in the Virunga range. In 1902, German captain Friedrich Robert von Beringe became the first Westerner to observe mountain gorillas on its slopes. The summit marks the tripoint of the DRC, Rwanda and Uganda, and the mountain lies within Virunga, Volcanoes and Mgahinga Gorilla national parks.

The name Sabyinyo comes from the Kinyarwanda word iryinyo, meaning "tooth". Locals call the mountain "Old Man's Teeth" because its serrated summit looks like worn teeth in a gum line, unlike the perfect cones of the neighbouring Virunga peaks. The summit also holds religious significance for local tribes.

The climb requires good physical fitness, as the ascent involves steep trails with some sections featuring handmade ladders. The best time to visit is during dry seasons when conditions are safest and visibility is clearest.

In 1902 the German captain Friedrich Robert von Beringe became the first Westerner to observe mountain gorillas on the flanks of Sabyinyo. The lava of the mountain is latite, a composition the French sources describe as unique among the Virunga volcanoes.