Exoplanet LP 791-18d is about 90 light-years away from Earth and is covered all over by volcanoes. With an atmosphere, there could be liquid water on the surface – a prerequisite for life as we know it.
One side of the planet is permanently brightly lit and hot, while the other side is constantly in the dark. The constant activity of the volcanoes would make the planet uninhabitable, even with water. Nevertheless, the presence of volcanoes provides research with new insights into evolution.