These volcanic domes on Venus are unique in the solar system. Each dome is about 25 kilometers across and up to 1 kilometer high. The domes appear to be made of thick volcanic lavas that would have erupted from beneath the surface into pancake shapes and then cracked to from concentric and radial patterns as they cooled. This mosaic image was made using data from the US Magellan radar-mapping spacecraft during the successive orbits of the planet in 1990.