On the Northern Slope of Arsia Mons: candidates Cavern Entrance (1)

Caption NASA:"Seven very dark holes on the North Slope of Arsia Mons (about 9° South Lat. and 239° East Long.) have been proposed as possible cave skylights, based on day-night temperature patterns suggesting they are openings to subsurface spaces. These 6 excerpts of images taken in visible-wavelength light by the Thermal Emission Imaging System (THEMIS) camera on NASA's Mars Odyssey orbiter show the 7 openings.
Solar illumination comes from the left in each frame.

The features have been given informal names to aid comparative discussion. They range in diameter from about 100 meters (328 feet) to about 225 meters (738 feet).
The candidate cave skylights are (A) "Dena", (B) "Chloe", (C) "Wendy", (D) "Annie", (E) "Abby" (left) and "Nikki", and (F) "Jeanne."

Arrows signify North and the Direction of Illumination".