Earth stands between Venus and Mars, and though the three planets could be compared to each other side by side, Earth is the only one with confirmed sign of life, we still have yet to find evidence of life on Mars while Venus is completely uninhabitable.
Much of the appeal of Venus comes from the fact that despite its horrifying modern appearance, it's actually really similar to Earth. "Picture a planet that's just like Earth but it's a little hotter because it's a little closer to the sun — and that would be Venus," David Grinspoon, a planetary scientist and astrobiologist at the Planetary Science Institute, told Space.com.
Along with Mars, these planets form a trio of worlds that began with comparable sizes, materials and temperatures — until suddenly, they were very different. Once upon a time, Venus, like Earth today, was covered in water, perhaps even habitable. Then, gradually, something fell out of whack.
Learn more about it on Meghan Bartels' article at Space.com.
(Image credit: Goddard Space Flight Center/NASA)