Abstract: A swivel joint apparatus for supplying utilities to a rotating building rotatable about a central axis has an inner, fixed spindle for securing to a fixed base of the building to extend co-axially with a central axis of rotation of the building, and an outer casing rotatably mounted on the spindle for securing to the rotatable part of the building. The spindle has a series of spaced annular flanges defining a series of annular chambers and at least one ring seal mounted on the peripheral edge of each flange for rotatable sealing engagement with the outer casing so that the casing forms an outer wall of each of the annular chambers. A lower end wall of the spindle has a plurality of ports for connection to fixed utility lines in the base for fluid supply to and from the building, each port connected through the spindle to a respective annular chamber.