The Martian surface is peppered with impact craters of all shapes, sizes and ages. However, many of the craters are just plain weird.
But just how 'weird' is weird?
Curious, Discovery News asked the High-Resolution Imaging Science Experiment (HiRISE) team which craters they considered to be the strangest. HiRISE is the most advanced camera to be put into Mars orbit. It is attached to NASA's Mars Reconnaissance Orbiter (MRO) and currently snapping features on the Red Planet's surface -- it has seen a ton of strange objects (sadly, it hasn't found a top secret military base yet, despite what you may have heard to the contrary). So, let's take a tour of some of the weirdest craters Mars has on offer...
Special thanks to Ari Espinoza of the HiRISE team for helping to compile this list (originally published Dec. 30, 2011. Updated May 7, 2013)