The LEGO Group has delved beneath the waves ten different times since first taking the plunge back in 1995. The advent of Aquazone ushered in a new era in which minifigures could be found in the deep. All of the themes and subthemes that followed — Aquaraiders, Hydronauts, Stingrays, Divers, Alpha Team, Mission Deep Sea, Aqua Raiders, Atlantis, Deep Sea Explorers — can trace their origins back to the Aquanauts and Aquasharks. These warring factions, with vaguely defined motives, are the original undersea adventurers.
Aquazone hit shelves in 1995 as the 5th official LEGO theme, the first to be released since Pirates six years earlier. It pitted the Aquanauts and Aquasharks in battle to obtain the chrome plated Hydrolator Crystals, which were needed — according to the official storyline — to breathe underwater. I didn’t question it at the time but looking back on it now that seems like very circular logic. They need to collect a McGuffin which allows them to breathe so they can stay in the deep to keep looking for… a McGuffin which allows them to breathe. Maybe nuclear war had scorched the atmosphere driving mankind to live beneath that waves? Going kind of dark there, LEGO designers.
The Hydrolator Crystal motivation was used in all the Aquazone stories, with them becoming more difficult to find requiring better technology which informed the looks of the subs and ferocity of the rivalries. Later themes employed more believable motivations such as finding sunken treasure, often guarded by ferocious sea creatures. Yet whether the theme was more reality based like Deep Sea Explorers, or set in the world of science fiction like Atlantis, all of them can be traced back to the Aquanauts and Aquasharks.