NASA’s Mars Curiosity rover captured stunning images last week of layered rock formations on the red planet's surface. NASA’s Jet Propulsion Laboratory The photos show Martian buttes and mesas, which were formed by erosion and sandstorms. Curiosity Project Scientist Ashwin Vasavada said studying the formations up close helped researchers further understand how sand dunes were buried before becoming "chemically changed by groundwater, exhumed and eroded to form the landscape that we see today.”