The European Space Agency's Mars Express mission has captured an image showing a section of an ancient channel where water once flowed on Mars.
The channel is Shalbatana Vallis, which can be found near Mars’s equator, and the image shows the northern section of the channel, which is about 800 miles (1,300km) long.
More on Mars
Water on Mars
While Mars today is a cold, barren planet with no immediate signs of life, it was once much warmer and wetter.
Planetary scientists have discovered a wealth of evidence over the past few decades that liquid water once flowed on Mars in the form of rivers, lakes and even oceans.
The evidence of this can be seen today, such as in the form of ancient channels like Shalbatana Vallis.
Scientists say Shalbatana Vallis formed 3.5 billion years ago by groundwater rising up to the Martian surface in enormous quantities.
After flooding this section of the surface of Mars, the water then ran downhill, eroding the rock and producing the winding valley seen in these images.
The main valley is about 6 miles (10km) wide and 0.3 miles (0.5km) deep.
Scientists say Shalbatana Vallis was likely deeper in the past, but has been filled in over centuries with different natural materials on the surface of Mars.
This includes volcanic ash, which can be seen in Mars Express images as dark blue material, and was blown across the planet by its strong winds.
Data from the Mars Express spacecraft was also used to capture this image, showing a strange bulge in the channel.
Scientists say it probably formed when ice trapped below the surface of Mars began to melt, causing the ground to collapse.
In the image, the dark material on the left of the bulge is volcanic ash.
Today, Mars doesn't have any known active volcanoes, but it is home to Olympus Mons, the largest volcano in the Solar System.
Also visible in the image are impact craters, caused by space rocks smashing into the Martian surface.
The rest of the terrain is smooth, which, scientists say, indicates it was once flooded by lava. In some places, this lava crumpled as it cooled, which causes the 'wrinkle ridges' seen in the image.
