http://www.esa.int/Our_Activities/Operations/Mars_Webcam_goes_pro

In this remarkable movie, the Visual Monitoring Camera (VMC) on Mars Express was used for the first time to image the limb of Mars during most of a complete orbit, showing in good detail the atmosphere seen ‘on edge’ at the apparent border between the planet’s surface and space.

The movie was stitched together from a series of 403 still images acquired by the camera during 13:45–19:09 GMT on 29 April 2016, during orbit 15624.

The spacecraft was commanded to turn as it orbited Mars, which kept the camera pointing at the brightest point on the horizon as Mars Express passed over the southern hemisphere.