Aegir is a highly advanced underwater megalopolis located directly below Cryptocity. The only one known in existence on the planet. Its technology is astoundingly remarkable. A robust ecosystem that provides unlimited oxygen through a system of machinery that pulls air from the surface and transfers it throughout all of the physical constructs within its environment. It maintains all of the essentials of any major civilization including living quarters, stores, entertainment centers, farming, schooling, business entities, mass transit in both tunnel systems and through the water itself, and then some. It is overseen by Big Willie, a gigantic whale being who is considered to be the titan and ruler of the sea. It is also home to "Crackin", the genius but also "hip" octopus.
With some of the most abundant plant and animal life in the ocean, species that are found nowhere else on earth, it is the closest thing to another planet. While aesthetically amazing, it is important not explore into unchartered territory. Incredible drops in temperature, increases in pressure, and loss of visibility can happen in an instant. Not to mention this is home to some of the largest and most dangerous creatures in the world.