An Unusual Hole in Mars

What created this unusual hole in Mars? Actually, there are numerous holes pictured in this Swiss cheese-like landscape , with all-but-one of them showing a dusty, dark, Martian terrain beneath evaporating, light, carbon dioxide ice . The most unusual hole is on the upper right, spans about 100 meters, and seems to punch through to a lower level. Why this hole exists and why it is surrounded by a circular crater remains a topic of speculation , although a leading hypothesis is that it was created by a meteor impact. Holes such as this are of particular interest because they might be portals to lower levels that extend into expansive underground caves . If so, these naturally occurring tunnels are relatively protected from the harsh surface of Mars, making them relatively good candidates to contain Martian life . These pits are therefore also prime targets for possible future spacecraft, robots , and even human interplanetary explorers .