A lava lake is an extraordinarily rare thing. Only a handful exist anywhere on Earth, and Nyiragongo's is the biggest of them all. The lava inside the crater swirls and churns constantly, sending up fountains of bright orange fire and filling the air with a strange red glow that can be seen from miles away at night.
Scientists travel to Nyiragongo from around the world to study how volcanoes work. By watching the lava lake, they can learn about what is happening deep inside the Earth, where temperatures are hot enough to melt rock. Nyiragongo sits inside Virunga National Park, making the park even more extraordinary.
The lava from Nyiragongo is unusual because it contains very little silica — a mineral that usually makes lava thick and slow. Nyiragongo's lava is much more runny and flows faster than almost any other lava in the world, which makes it one of the most closely watched volcanoes on the planet.
Hiking to the crater rim of Nyiragongo takes several hours on steep jungle trails. At the top, the air smells faintly of sulphur, the ground is warm underfoot, and when you peer over the edge, there it is — a swirling lake of fire far below, glowing like the sun had moved underground.