Wide, flat domes that resemble pancakes highlight this image of Venus. The domes in the picture are almost 40 miles wide, but only a few thousand feet tall, bordered by sheer cliffs. The domes probably formed when thick molten rock bubbled to the surface and spread out in all directions. It continued to spread well after the lava spigot was turned off. Dozens of pancake domes have been spotted on the planet. [NASA/JPL]
Find out more in our radio program entitled Moon and Venus.