Terra-Sphere Control tower

The  was one of the towers built by Dollar Intergalactic for terraforming Isen VI in 25th century. This tower was the headquarters of the Terra-Sphere Control.

The foundation for the tower was a terraformer missile that hit the ship of Rann-Korr. This gave the Hyperion access to and control over the whole terraforming process.

When the Terra-Sphere Control detected the Twelfth Doctor and Clara Oswald's arrival, the intruders were brought to the tower. (COMIC: Terrorformer)