Venus is similar to Earth in many ways. The planets are almost the same size, but they have developed very differently since their formation 4.5 billion years ago. Almost nothing is known about the early days of Venus because observations made by spacecraft reveal a surprise – about half a billion years ago, there was a global cataclysm on the planet as tens of thousands of volcanoes erupted and reshaped the entire planetary surface. Traces of anything that existed before were almost completely erased. One tenth of the surface has structures, reminiscent of Earth's continents, that may have survived the global volcanic catastrophe. This perspective image created using radar data from NASA's Magellan mission shows the eight-kilometre-high Maat Mons volcano, with solidified lava flows in the foreground.