As it sped away from Venus, NASA's Mariner 10 spacecraft on February 7, 1974, captured this seemingly peaceful view of the planet, nearly the size of Earth, wrapped in a dense, global cloud layer. The clouded globe of Venus is a world of intense heat, crushing atmospheric pressure and clouds of corrosive acid. NASA/JPL-Caltech via REUTERS.

This computer-generated perspective view of the highland of Ovda Region on Venus shows Magellan radar datasuperimposed on topography. The image was released by NASA May 26 and it was made up of compilation of radar images collected during all three of Magellan's eight month mapping cycles

The planet Venus is seen in this photograph taken by the Galileo spacecraft?s Solid State Imaging System on February 14, 1990. Picture taken February 14, 1990. NASA/JPL via REUTERS.

Data from NASA's Magellan spacecraft and Pioneer Venus Orbiter is used in an undated composite image of the planet Venus. NASA/JPL-Caltech/Handout via REUTERS.

The hemispheric view of Venus, as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission, is centered at 180 degrees east longitude is seen as published on June 4, 1998. NASA/JPL/USGS/Handout via REUTERS.