The Drum

 was an underwater mining facility in Scotland in 2119.

Once it used to be a city, but when a dam broke, the city was flooded and destroyed,

Since the facility was underwater and there was no natural light. The facility could go into day mode or night mode.

The base was visited by the Twelfth Doctor and Clara Oswald who arrived by orders from the TARDIS, when the base was haunted by ghosts. (TV: Under the Lake)

Crewmembers

 * Cass
 * Lunn
 * Mason Bennett
 * O'Donnell
 * Richard Pritchard (formerly)
 * Jonathan Moran (formerly)