Titans Tower

The Titans Tower is the Teen Titans' base of operations, built by the Titans. It is located on an island in the Jump City bay. Each Titan has his or her own room. Its Main Ops room also serves triple-duty as a living room and kitchen. It also has training facilities both inside and outside, as well as a gym, for the Titans to stay in shape.

A similar version is built for the Titans East, but it has been built on the side of a cliff, not on an island, near the coast of Steel City. In Teen Titans: Trouble in Tokyo, the Tower's location (as well as the location of Jump City) is revealed to be near California.

Rooms

Living/Main Ops Room (has the flat panel computer displays, kitchen, refrigerator, TV, and power storage of the tower, and also houses the Tower's main computer and communication suites. One wall is made entirely of glass from floor to ceiling, allowing the Titans to look out over the bay and Jump City)
Entryway (with couches and chairs along a narrow hallway; seen in "Final Exam" and "Can I Keep Him?")
Two confirmed Bathrooms (pink shower curtain and bath rugs suggest that one is the girls' preferred bathroom, although it is a unisex restroom judging by the sign on the door, and the other bathroom consisting of a black and white checkered floor with a bathtub which has a blue shower curtain)
Robin's Room (queen-sized bed with blue sheets, bookcase and filing cabinets, has a spartan, dojo sort of feel to it -- not much decoration and lots of white walls and brown woods and cupboards)
Cyborg's Room (has a System Recharger for Cyborg's artificial systems, a personal computer, TV, and other electronic gear, has a wall of photographs and a display case full of trophies, sleeps on a computer table)
Starfire's Room (tomboy kind of atmosphere, circular-shaped bed with redish pink sheets and matching curtains)
Beast Boy's Room (has a bunk bed with purple sheets, a ton of junk and trash, VERY messy room)
Raven's Room (filled with mystical, girly artifacts and sculptures, a trunk, and a ton of books, circular bed in the center of her room with ornate headboard and purple-blue sheets)
Gym (seen in "Divide and Conquer", "Sisters", "Only Human", "The Beast Within", and "Overdrive")
Terra's Room (large, open room with an outdoor-nighttime theme painted onto the walls and ceiling, currently unoccupied)
Basement (used for storage, very dark)
Roof (contains a basketball court where the Titans shoot hoops, is a favorite place of reflection for the Titans as well, and contains a volleyball court)
The Sick Bay/ Infirmary (curtain between two sick beds, dark room with a wide window seen in the episode "Haunted")
The Evidence Room (filled with all the types of weapons, evidence, and gear they picked up from their enemies, such as Slade or Control Freak)
T-Ship Rocket Launch Shaft (situated off the island)
T-Ship Launch Site
Garage (houses Cyborg's T-Car and Robin's R-Cycle)
Game Room (Cyborg built it in "Overdrive")
Laundry Room (In "Transformation", Starfire is seen washing Beast Boy's underwear in this room. The full view of the room is shown in the "Utility Player" short)

Others Who Inhabited the Tower

Terra (before she betrayed the Teen Titans in Betrayal)
Control Freak (for about at least half an hour in "For Real")
Mammoth, Gizmo, and Jinx (captured it in "Final Exam")
Mother Mae-Eye (took it over and induced mind-control over the Titans with pie in "Mother Mae-Eye")
Silkie (starting after "Date with Destiny", but before "Can I Keep Him?", and permanently later on)
Titans East (came to watch the city when the Teen Titans were off battling the Brotherhood of Evil in "For Real")
All Titans and Honorary Titans (such as Hot Spot, Kid Flash, and Red Star at the end of "Titans Together" for at least a couple of minutes)
Blackfire (during "Sisters")
Killowat (prior to Teen Titans Go! issue #48 Wrong Place Wrong Time)
Mr. Wolf (requested Beast Boy to watch over him before turning into a werewolf in Teen Titans Go! issue #13 What Time is it, Mr. Wolf?)
Madame Rouge (disguising as Wildfire in Wildfire)

Errors

At the conclusion of "The End - Part 3", Raven and Robin have a moment together at the window of the Main Ops room. However, the bridge of Jump City can be seen in clear view from this point, despite that the bridge is not within the line of sight of the Ops room.
When the Titans and all Honorary Titans return to Titans Tower at the end of "Titans Together", the base of the structure appears wider than it usually is in the wide shot.
In "The End - Part 2", the angle of the ruined tower changes between shots. When the Titans first attempt to attack Trigon, Titans Tower was at a steep angle, while in subsequent shots and the following episode, returns to an upright position.
The number of windows (excluding the Ops room window) going from up to down on the outside view of the tower remains inconsistent throughout the series. The tower is most commonly seen with Season 4, though at times one sees it with Season 5 or more.

Future

Titans Tower in the episode "How Long is Forever?" has taken neglect and damage over the years due to the timeline where Starfire has gone missing. The Tower now has no power, damaged windows and cracks and covered in ice and snow. The only person to inhabit the tower was Cyborg.

List of absences

"The Sum of His Parts"
"Mad Mod (episode)"
"Bunny Raven... or ...How to Make A Titananimal Disappear"
"Stranded"
"Homecoming - Part 2"
"Trust"
"Snowblind"
"Kole"
"Hide and Seek"
"Lightspeed"
"Revved Up"
"Go!"
"Calling All Titans!"

Teen Titans Go!

New Teen Titans

Trivia

It should be interesting to note that Robin and Starfire, as well as Beast Boy and Raven, each have their rooms on the same side of the tower, while Cyborg shares the same side as Robin and Starfire.
Raven once mentioned that she should consider re-decorating her room (albeit as a joke to the audience) in the episode "Fear Itself".
Cyborg has the capability to merge with Titans Tower to perform one powerful sonic blast. This was seen during Slade's attack on the tower in "The End - Part 1".
Titans Tower has been known to sustain some noticeable damage over the course of the series, such as being nearly completely ruined on the inside and out in "Betrayal", a massive trench created by a blast from Professor Chang's disintegrator cannon in "X", being totally destroyed (while still maintaining its shape) and repurposed as Trigon's throne in "The End - Part 2" and "The End - Part 3", and being bombarded by Saico Tek's exploding shurikens in Teen Titans: Trouble In Tokyo.
Silkie is a larva that inhabits the tower, who is kept as a pet by the Titans. He unofficially begins living with them following "Date with Destiny" and then officially after "Can I Keep Him?". He has been known to make blink-and-you-will-miss-it cameos within the tower and outside of it.
"Transformation" hints at the impression that the Tower contains only one bathroom, which, statistically speaking, makes no sense for a building that huge, much less one that serves as the base of operations for at least five superpowered warriors (even if, at the end of the day, it is just a house).

Gallery

Concept Art

Locations
Jump City	Amusement Park \| Bank of Pérez \| Ben's \| Cardy Park \| Central Park \| Cook's Electronics \| Crash Alley \| GameStation Labs \| H.I.V.E. Tower \| Jump City Arena \| Jump City Bank \| Jump City Museum \| Jump City Playground \| Jump City Stadium \| Jump City Zoo \| Killer Moth's Laboratory \| Mad Mansion \| Mega Meaty Meat \| Murakami School \| Ocean World \| Old Stadium \| Pizza Corner \| The Nightclub \| Titans Tower \| Tito's Junkyard \| Video Dome
Cities/Countries	Gotham City \| Japan (Tokyo) \| Markovia \| Morocco \| Paradise Island \| Paris \| Shahrazad \| Steel City \| Tinseltown \| United Kingdom
Worlds/Realms	Azarath \| Earth \| Larry's World \| Raven's Mind \| Sentien \| Swamp Moons of Drenthax IV \| Tamaran \| Vernathia
Others	Antarctica \| Dark Way Prep \| H.I.V.E. Academy \| Junior H.I.V.E. Academy \| Shark Island