Today, the surface temperature of Venus is 864 degrees and its atmosphere is thick and murky, consisting of carbon dioxide and nitrogen.
But a computer model that NASA developed reveals that that planet was once a lot cooler. About 715 million years ago, it may have had oceans made of liquid water and a temperatures that would have been possible for humans to live in. (The image above is a simulation of what the planet may have looked like.) Over time, however, the planet was exposed to a great deal of sunlight, causing its oceans to evaporate and generate its present atmosphere.
Amazingly, these life-supporting conditions were in place for up to 2 billion years. Who knows? An entire species of human-like creatures may have evolved and created a civilization.
You can read more over at NASA.