It may not be as hospitable as Hawaii's best, but the Martian volcano Olympus Mons nothing to shake a stick at.

Olympus Mons is the highest volcano in the Solar System and is five times larger than its biggest counterpart here on Earth. It measures some 342 miles (550 kilometers) across and rises to a height of about 15.5 miles (25 kilometers), about half the distance from the Mariana Trench (the deepest spot on Earth) to the top of Mount Everest.

This image, taken by the High Resolution Stereo Camera (HRSC) aboard the European Space Agency's Mars Express spacecraft, shows the volcano's complete caldera atop Olympus Mons' summit. The image itself is the first high-resolution picture of the caldera, which is about two miles (three kilometer, and spans an area about 63 miles (102 kilometers) wide. It was taken from orbit 169 miles (273 kilometers) above the Martian surface, with south pointing up, and has a resolution of about 39 feet (12 meters) per pixel.

Credit: ESA/DLR/FU Berlin (G. Neukum)