The Abyss

The Abyss is a movie starring Ed Harris, Mary Elizabeth Mastrantonio, and Michael Biehn. A civilian diving team is enlisted to search for a lost nuclear submarine and faces danger while encountering an alien aquatic species.
A civilian oil rig crew is recruited to conduct a search and rescue effort when a nuclear submarine mysteriously sinks. One diver soon finds himself on a spectacular odyssey 25,000 feet below the ocean's surface where he confronts a mysterious force that has the power to change the world or destroy it.