In the 1970s, NASA hired some artists to visualize life in three kinds of space colonies. Here, we’ve got a Bernal Sphere, a “point design with a sphere living area,” or, more simply, a hollow sphere with air on the inside.
In this image, we’ve got a human-powered airplane (really, a hang glider) zooting across the low-gravity, high-air-pressure interior.
Not a bad way for us to get a foothold in space.