11 February 1967: broadcast of first episode of The Moonbase. The Tardis lands on the Moon, near the base which controls Earth's weather. Crew members are falling ill; but it is the Cybermen behind it all.
11 February 1978: broadcast of second episode of The Invasion of Time. The Doctor expels Leela from the Capitol, and laughs as three alien beings materialise in the Panopticon.