Carrying Scientists Into Sinkholes to Study Frogs - Joe Riis

Tepuis are high table-top mountain plateaus that exist in the jungles of South America. The ecological islands have high populations of plants and animals found nowhere else. To study frogs, photographer Joe Riis, biologist Bruce Means and mountain climber Mark Synnot made an expedition to one tepuis. The trip involved lowering the 71-year old Means into a deep sinkhole, and tethering the non-climber frog expert to a series of shrubs to anchor his escape. Riis captured the expedition in his film "Return to the Tepuis".