Atlantis command tower

From The Stargate Omnipedia

Atlantiscommandtower2.jpg

An impressive tower standing tall in the center of the city of Atlantis. The structure contains the Stargate, command center, V.R. room, Puddle Jumper bay, the base commander's personal office, and more. It is believed to have originally been the chief outpost for all Ancient planets in the galaxy.

The command tower is now used by the Atlantis expedition team from Earth as an operations post while they explore the Pegasus Galaxy and wage their battle against the Wraith.

KEY EPISODES

Rising, Part 1 - The Earth team arrives through the Stargate in the command tower, eager to begin their exploration of the various parts of the facility.
The Return, Part 2 - Sheppard's team detonates a bomb in the Gate Room after the Replicators take Atlantis, destroying the command tower. But the Replicators rebuild it in a matter of hours.
First Contact - The tower suffers heavy damage when an alien technology nearly destroys the Stargate.