Active lava lakes are found beyond Earth

This Voyager 1 image mosaic shows a large area of Io's volcanic plains, with numerous volcanic calderas and lava flows. Loki Patera, an active lava lake 1,000 times large than Kīlauea Volcano's summit lava lake, is the black horseshoe-shaped feature in the lower part of the image. Credit: NASA/JPL/USGS