The same thing seems to be happening, more or less, along a cliff face at the edge of Mars's north polar ice cap. Aboard the orbiting Mars Reconnaisance Orbiter, the powerful HiRise Camera (the best ever to orbit another world) took an enormous, high-res image that included a long polar cliff. Amazingly, the image caught four widely separated landslides in progress along the 2,300-foot-high cliff — all at once! That's one place on Mars I wouldn't want to be exploring on foot.
"It really surprised me," says discoverer Ingrid Daubar Spitale. "It's great to see something so dynamic on Mars. A lot of what we see there hasn't changed for millions of years."