The Caloris Basin, shown here in a 1 kilometer per pixel mosaic, is one of the largest basins in the solar system, its diameter exceeds 1300 kilometers and is in many ways similar to the great Imbrium basin on the Moon (diameter >1100 kilometers). To enhance landforms a highpass filter was used in processing.

The Mariner 10 mission, managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, explored Venus in February 1974 on the way to three encounters with Mercury-in March and September 1974 and in March 1975. The spacecraft took more than 7,000 photos of Mercury, Venus, the Earth and the Moon.