(Marcus Lowth) Sometimes referred to as USOs (Unidentified Submerged Objects) or UUOs (Unidentified Underwater Objects), sightings of strange lights and crafts emerging from, or descending into, the seas, oceans, and lakes around the world are quite widespread. Some UFO researchers and investigators even claim that there are underwater alien bases present in the vicinity of these aquatic sightings. Here are 10 of the most interesting claims.