You're looking at an image of Tharsis Tholus, an extinct Martian volcano that by Earthly standards is positively massive: towering 8km above its surrounding terrain, the dormant giant's tallest peak almost matches that of Mt. Everest.

But compared to other Martian volcanoes, Tharsis Tholus is of pretty average height. What makes it special is its bizarre, battered condition, revealed here through the use of color-coded topographical labeling. Hi-res images after the jump.

According to the European Space Agency:

Shown here in images taken by the HRSC high-resolution stereo camera on ESA's Mars Express spacecraft, the volcanic edifice has been marked by dramatic events.

At least two large sections have collapsed around its eastern and western flanks during its four-billion-year history and these catastrophes are now visible as scarps up to several kilometres high.

The main feature of Tharsis Tholus is, however, the caldera in its centre.

It has an almost circular outline, about 32 x 34 km, and is ringed by faults that have allowed the caldera floor to subside by as much as 2.7 km.

It is thought that the volcano emptied its magma chamber during eruptions and, as the lava ran out onto the surface, the chamber roof was no loner able to support its own weight.

So, the volcano collapsed, forming the large caldera.

According to ESA, elevation data is color coded, with purple indicating the lowest lying regions and beige the highest.