The most promising places to search for life beyond Earth and to build extraterrestrial habitable stations are caves on planets, their moons, asteroids, and comets.
Reasons:
Caves have already been discovered on Mars and other habitable bodies, but they have not yet been explored because there are no caving robots. They need to be created, and this work has already begun. New, unconventional ideas are needed to study space underground!
Vladimir Surdin, candidate of physical and mathematical sciences, senior researcher at the P. K. Sternberg State Astronomical Institute, associate professor at the Faculty of Physics of Moscow State University. Winner of the Belyaev Prize and the Enlightener Prize.