See the Mysterious Photos of Water on Mars

Recurring slope lineae (RSL) are a type of dark streak seen on Martian slopes and are thought to form from flow of liquid water. This image shows RSL in the Aram Chaos, acquired on Jan. 11, 2015.

This image shows the central peak in Porter Crater, acquired on April 17, 2015.

RSL may be due to active seeps of water. These dark flows are abundant along the steep slopes of ancient bedrock in Coprates Chasma. Acquired on Dec. 31, 2013.

Ravines (or very large gullies) are actively forming on Mars during the coldest times of year, when carbon dioxide frost aids mass wasting. In this image, acquired on March 25, 2015, we see warm-season flows in cold-season ravines.

An image of the southeast rim of Hale crater, acquired on Nov. 13, 2014

This RSL is one of the most active sites known on Mars in the central peaks of Hale Crater, acquired on Feb. 20, 2015.

A RSL in Raga Crate, acquired on Feb. 9, 2015.

A surprise landslump in Melas Chasma, acquired on Jan. 15, 2014.

An image of the southeast rim of Hale crater, acquired on Nov. 13, 2014.

This image was acquired in southern winter over part of Asimov Crater, on March 15, 2014, showing the equator-facing slope of a deep trough inside the crater.

RSL along Coprates Chasma Ridge, acquired on July 7, 2013.

Seasonal flows on Palikir Crater, a warm Martian slopes, that may be caused by the flow of salty water on Mars. Acquired on March 15, 2013

RSL in Juventae Chasma, acquired on Jan. 18, 2013.

This image displays a site along a Coprates Chasma ridge shows RSL on generally north-facing slopes, acquired on Oct. 20, 2012.

Right past the sharp, but warped rim of this ancient impact crater are deposits of winter frost, which show up as blue in enhanced color. Acquired on July 16, 2012.

Slope features seen on a wall in Newton crater acquired on May 30, 2011.