Wearing khaki green and toting AK-47 assault rifles, the rangers of Virunga National Park in the Democratic Republic of Congo have some of the most dangerous jobs in conservation.

Virunga, a UNESCO World Heritage site located in one of the most violent places on earth, is under threat from armed militias, poaching, and potential oil exploration.

The park, the oldest and most biodiverse in Africa, is home to around one-quarter of the world’s mountain gorillas – a critically endangered species – as well as a huge variety of other wildlife.

A new documentary about the park tracks the efforts of those trying to save it in the face of increasing conflict. Director Orlando von Einsiedel, who spent two years filming in the park, says: ‘Despite 20 years of living through warfare, the rangers of Virunga have an incredible vision for their country and infectious optimism.’