Lava lakes on the surface of Jupiter’s moon Io

Io has the most geologically active surface in the entire solar system, due its elliptical and close orbit to Jupiter, creating a huge amount of friction and heat within the moon.

As a result, there are at least 400 active volcanoes scattered across its surface, with over 130 erupting at any given time. Volcanic plumes can reach as high as 400 km (250 mi). The photo on the left is of the Tupan Patera volcano.