The Morlock Sphere is a massive construction built around the Sun, by the Morlocks of Timeline C in the year 657,209. It houses the bulk of the Morlock species, as well as a number of other forms of Humanity.
The Morlocks didn't create the sphere by breaking apart the planets in the solar system since even combined the mineral wealth wouldn't be enough to create the sphere. So, they used the sun's own solar material lifted off by a fleet of ships with shaped magnets, which created a strong enough field to lift off the material and shaped it into the sphere. Periodically, the Morlocks would lift off more material and increase the width of the sphere. ("The Time Ships")
The interior of the outer layer of the sphere houses Morlock society. In this timeline, Morlocks represent the main portion of Humanity, and the most advanced portion.
The layer of the Sphere closest to the sun is inhabited by a number of humans, holding "primitive" physical forms, which range from current-day Humanity to Neanderthal Man, to various other types of Humans. Unlike the Morlocks, these often engage in wars with each other.