Wingsuit / BASE-jump athlete Alexander Polli does the never before done-a tactical flight through a narrow cave on a rugged mountainside. The flight starts with a jump from a hovering helicopter, Alexander reaches speeds of 250 km/h (155 mph) while following a precise trajectory leading to the cave opening, he then fully commits and flies directly through the narrow opening of the "Batman Cave!"

The project page describes this crazy-stupid-amazing-daring video as:

Wingsuit / BASE-jump athlete Alexander Polli does the never before done—a tactical flight through a narrow cave on a rugged mountainside. The flight starts with a jump from a hovering helicopter, Alexander reaches speeds of 250 km/h (155 mph) while following a precise trajectory leading to the cave opening, he then fully commits and flies directly through the narrow opening of the "Batman Cave!"