High Templar: "Ah, so you want to learn more about Markiors city? Well, take a look here:"

Basic:
The Protoss Nexus. Main building.

A Protoss Pylon. Buildings must be near a Pylon to warp in, except for an Assmilator or Nexus.

Assimilator. Uzsed for getting Vespene gas from Geysers.

Gateway. Warps in Zealots, Dragoons, High Templar and Dark Templar.

A Forge. Needed to warp in Photon Cannons.

A Photon Cannon. Detects burrowed or invisible units. Shoots em down, too...

Cybernetics Core. Technoligy is needed to warp in advanced buildings.

Advanced:
A Stargate. Warps in flying Protoss technoligy. Scouts, Corsiars, Arbiters and Carriers.

Citadel of Adun. Needed to warp in a Templar Archives.

Templar Archives. The wisdom center of the Protoss. Used to make a gateway able to summon High Templar and Dark Templar.

Fleet Beacon. Makes Stargate able to warp in Carriers.

Arbiter Tribunal. Combined with Templar Archives, you can warp in Arbiters from the Stargate.

Miscellaneous information:

The Shield Battery. Contains enough psionic power on its own to recharge the Psi Shield of Protoss beings.

The Protoss Robotics Facility. Here is where Reavers, Shuttles and Observers are constructed.

The Robotics Supporting Bay. With the added technoligy of the structure, Reavers can be constructed in the Robotics Facility.

The Observatory. Used for researching Observer technoligy.