This machine looks like it should be creating a new biosphere on Mars, but instead it's bringing solar power to Europeans on cloudy days. Called a "heat accumulator," this massive, silvery ribbon of solar-power-sucking panels can store energy all day and then feed it to the power grid at night. German aerospace engineers put it into operation in Spain earlier this month, and are hoping it can help make solar energy viable in areas without much sun. Photo by DLR/Markus Steur.