The Eisriesenwelt—the "World of the Ice Giants"—is an Austrian cave that stays cold enough year-round to freeze any water that gets into it. As a result, the cave is full of massive ice formations. On April 28th, it was also full of people like physicist Daniel Schildhammer (seen above) who came to the cave to test out a wide array of space technologies, from protective suits to roving robots. It's all part of an international effort to prepare for a mission to Mars. Caves on Mars are likely place where bacteria and other forms of microbial life might be hiding out—the temperatures stay steady underground and the cave would protect those microbes from cosmic rays. Below: Another scientist tests out a rover meant to scale cliffs.
Images: REUTERS/Lisi Niesner