Alexander Polli, a skydiver and pioneer in BASE jumping, died after a wingsuit crash in the French Alps. Polli, 31, crashed into a tree while jumping in the Couloir Ensa near Chamonix shortly after 5 a.m. EDT on Monday, PGHM mountain rescue officials told NBC News. Polli died at the scene, which is popular – and dangerous – for BASE jumpers. “It’s a location where there are a lot of accidents,” a PGHM rescuer who gave his name only as Mercer told NBC. The World Wingsuit League wrote on Facebook that “Alex was known for his hard-core proximity lines and that legacy continues to inspire new generations of jumpers for years to come.