Billions of years ago, Venus had as much water as Earth, but at some point in its evolution, clouds of carbon dioxide in the planet’s atmosphere triggered the most intense runaway greenhouse effect in the Solar System. This led to a sharp increase in temperature to the levels observed today. This, in turn, caused the planet’s water to evaporate, disappearing into space. Meanwhile, Venus’s atmosphere at cloud level rotates approximately 60 times faster than the planet itself—a phenomenon known as superrotation.