This anaglyph image of Tharsis Tholus was acquired using the nadir channel and one of the four stereo channels of the High Resolution Stereo Camera on board Mars Express, which are directed obliquely towards the planet’s surface. When viewed using red-cyan glasses, the landscape can be seen in 3-D. The distinctive two and a half kilometre deep caldera and the partially collapsed flanks of the volcano are visible in this 3-D view. The image also shows the numerous lava flows on the Red Planet. Taking into account the number and massive extent of these lava flows, it is possible that Tharsis Tholus is ‘submerged’ in lava to a depth of several kilometres.