New images from Mars, taken by NASA's Mars Odyssey spacecraft and the Mars Global Surveyor have shown what appears to be at least seven entrances to large caves on the slope of Arsia Mons, a Martian volcano.
All of the cave entrances, which were named "The Seven Sisters", are at least 100 to 250 meters (328 to 820 feet) in diameter.
While scientist have yet to find any conclusive evidence of life on Mars, this has done little to detract the Bush administration's plans for building a fence between the US and Mars to keep out any illegal aliens and to root out terrorist.