TARDIS were not, its weight would shatter the Earth's surface. In the tie-in novels, the interior of the TARDIS has been known to contain an entire city, encompass an entire parallel Earth, and even dwarf Gallifrey itself when turned inside out. A distinctive architectural feature of the TARDIS interior is the roundel. In the context of the TARDIS, a roundel is a circular decoration that adorns the walls of the rooms and corridors of the TARDIS, including the console room. Some roundels conceal TARDIS circuitry and devices, as seen in the serials "The Wheel in Space" (1968), "Logopolis", "Castrovalva" (1981), "Arc
City Circle Harbour Bridge. This section contains four tunnels. Two connected to the Harbour Bridge, while the two City Circle tunnels terminated at Wynyard. In 1956 the dead ends at St. James and Wynyard were joined and the "missing link", Circular Quay – was opened. Central and Circular Quay stations are above-ground (Circular Quay is elevated, directly underneath the Cahill Expressway), while the remainder are underground. Several unused railway tunnels also exist. The former tram tunnels at Wynyard, and other stub tunnels at St James are well known. The current service patterns generally consist of trains from the Bankstown & Inner West