Take, for example, the Antarctic ice shelves. Humans have never before explored the underside of these things, and never expected to find living creatures at such depth and cold and pressure. Scientists from NASA drilled a hole 200 meters down into an Antarctic ice shelf (the McMurdo ice shelf) and sent a camera down to take images of the underside of these ancient ice structures. They were very surprised to see, in one of the images, a small, orange arthropod. Check it.
Scientists also found a jellyfish living under the ice shelf. This is just one of a series of discoveries in the last decades that show that life, even complex-multi-cellular life, can exist in places where we would never have thought. This makes a case for the possibility that life of some sort could exist yet on some bizarre ecosystem under the surface or Mars for example, or under one of the frozen moons of Jupiter. Life is pervasive.
The hole is an 8 inch hole and the site is about 12 miles from the open ocean. The arthropod, technically a Lyssianasid amphipod, is very distantly related to the shrimp humans enjoy. Here is a video showing he little orange bastard in action.