Gagarin Base

Gagarin Base was a secret moonbase built by the Soviet Union and was named after cosmonaut Yuri Gagarin. Demetrius and his family worked on early construction in Odessa, Ukraine without knowing it was for a moonbase. It finished construction in January 1969.

The base was located in Mare Tranquillitatis and the American's secret  Horizon Base was just visible on other side of Plinius. (PROSE: Moon Blink)