The Moon

The Moon was one of Earth's moons, and apparently the first one. It's origin is unknown, but it apparently did not form with the Earth, and the Silurians reported that it did not appear in Earth's sky until their time. (DW: The Runaway Bride, Doctor Who and the Silurians)

Moon bases
Humans first built a base on the Moon in the mid to late 21st century. (DW: The Moonbase). However, previously in the late 20th century the Judoon built a base on the moon. (visittorchwood.co.uk, DW: Smith and Jones)