A rock containing many smaller round stones could indicate that there was once a large amount of liquid water on the Red Planet.

A Martian spacecraft spied a Martian rover rumbling through the red desert. The new image captured by NASA's Mars Reconnaissance Orbiter — which has orbited Mars since 2006 — shows the space agency's car-sized Curiosity rover traversing the terrain below as it scales the planet's 3.4-mile-high Mount Sharp.

“The discovery of abundant siderite in Gale Crater represents both a surprising and important breakthrough in our understanding of the geologic and atmospheric evolution of Mars,” Benjamin Tutolo, associate professor at the University of Calgary, Canada, and lead author of the paper, said in a statement.