The Landscape of Mars: Pictures

In this image provided by NASA's Mars Reconnaissance Orbiter, dark, narrow streaks on the slopes of Hale Crater are inferred to be formed by seasonal flow of water on surface of present-day Mars. These dark features on the slopes are called "recurring slope lineae" or RSL. Scientists reported on September 28, 2015 using observations with the Compact Reconnaissance Imaging Spectrometer on the same orbiter detected hydrated salts on these slopes at Hale Crater, corroborating the hypothesis that the streaks are formed by briny liquid water. NASA/JPL-Caltech/Univ. of Arizona/Getty Images
In this image provided by NASA's Mars Reconnaissance Orbiter, dark, narrow streaks on the slopes of Garni Crater are inferred to be formed by seasonal flow of water on surface of present-day Mars. NASA/JPL-Caltech/Univ. of Arizona/Getty Images
The High-Resolution Stereo Camera on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. Echus Chasma is the source region of Kasei Valles which extends 3000 km to the north. The data was acquired on September 25, 2005. ESA/Getty Images
In this image provided by NASA/JPL-Caltech/MSSS this self-portrait of NASA's Curiosity Mars rover shows the vehicle at the "Mojave" site, where its drill collected the mission's second taste of Mount Sharp. The scene combines dozens of images taken during January 2015 by the MAHLI camera at the end of the rover's robotic arm. NASA/JPL-Caltech/MSSS/Getty Images
This undated photo made available in London Wednesday February 16, 2005, was taken by the NASA Hubble Space Telescope of the planet Mars. AP Photo/NASA Hubble Space Telescope
This image sent by NASA’s Opportunity rover, January 7, 2015 shows a view from atop a hill on Mars. AP Photo/NASA
In this photo provided by NASA, a view of the lower reaches of Mount Sharp is shown in a cropped image taken with a 34-millimeter Mast Camera on NASA's Curiosity rover, August 18, 2012 on Mars. NASA/Getty Images
The High-Resolution Stereo Camera (HRSC) on board ESA’s Mars Express has returned images of Echus Chasma, one of the largest water source regions on the Red Planet. The data was acquired on September 25, 2005. ESA/Getty Images
In this image provided by NASA/JPL-Caltech/MSSS from the Navigation Camera on NASA's Curiosity Mars rover shows wheel tracks printed by the rover as it drove on the sandy floor of a lowland called "Hidden Valley" on the route toward Mount Sharp. The image was taken during the 709th Martian day, or sol, of the rover's work on Mars August 4, 2014. NASA/JPL-Caltech/MSSS/Getty Images
In this image composite provided by NASA/JPL-Caltech/MSSS, NASA's Curiosity Mars rover used the camera at the end of its arm in April and May 2014 to take dozens of component images combined into this self-portrait where the rover drilled into a sandstone target called "Windjana." NASA/JPL-Caltech/MSSS/Getty Images
The largest crater in this mosaic of images taken by the Context Camera on NASA's Mars Reconnaissance Orbiter is Endeavour Crater, which is 22 kilometers (14 miles) in diameter. The team operating NASA's Mars Exploration Rover Opportunity in the Meridiani Planum region of Mars chose to drive the rover toward Endeavour after Opportunity ascended out of smaller Victoria Crater in August 2008. NASA/Getty Images
Mars' own Grand Canyon, Valles Marineris, is shown on the surface of the planet in this composite image made aboard NASA's Mars Odyssey spacecraft. The image was taken from a video featuring high-resolution images from Arizona State University's Thermal Emission Imaging System multi-band camera on board the spacecraft. The mosaic was then colored to approximate how Mars would look to the human eye. NASA/Arizona State University/Getty Images
In this image provided by NASA/JPL-Caltech/MSSS, and captured by NASA's Curiosity rover, a rock outcrop called Link pops out from a Martian surface that is elsewhere blanketed by reddish-brown dust, showing evidence for an ancient, flowing stream, September 2, 2012. NASA/JPL-Caltech/MSSS/Getty Images
in this image provided by NASA/JPL-Caltech/MSSS, NASA's Curiosity Mars rover recorded this view of the sun setting at the close of the mission's 956th Martian day, April 15, 2015, from the rover's location in Gale Crater, Mars. NASA/JPL-Caltech/MSSS/Texas A&M Univ/Getty Images