|To give you an idea of the scale of the inner crater: that's a person in the lower left.|
Mount Nyiragongo is a volcano located in the Democratic Republic of the Congo. Vulcanologists visit active volcanoes to study them with the hope of one day being able to predict eruptions. The Nyiragongo Crater is particularly attractive to scientists because it sports the largest lava lake in the world.
Boston's 'The Big Picture' has some amazing photographs by French photographer Olivier Grunewald who travelled to Africa with a team of scientists and climbed down into the crater for a closer look. The results are terrifyingly beautiful.