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This article is about the xel'naga-crafted observation structure. You may be looking for: the protoss structure observatory

The xel'naga tower[1] (formerly xel'naga watch tower[2]), also known as an observation post or observatory, is an ancient xel'naga structure.[3][4]

When activated, the observatory illuminates and crafts itself together into a watch tower.[5]

Game Effect[]

An inactive tower.

The tower is a neutral structure which grants a greater viewing area to units that activate it[4][6]; it can only be activated by ground units.[7]
Burrowed and flying units cannot activate a watch tower but cloaked units can.[8]
Auto-turrets cannot activate a watchtower as they are Structures.[7]
The visual radius (22) is greater than that of an observer (11, 16.5 deployed).[9]

Xel'naga towers do not grant detection.[10][9]

These are usually placed in strategic areas.[4]
A player can quickly tell what an enemy is attacking with, making upcoming battles easier and blunting the effect of rushes.[9]
A player attempting a rush is advised to try to hide rush attacks.[11]

If units from two opposing teams are in control range (2.5) of a watch tower, neither will have control over it.[12]

Watch towers are highlighted on the mini-map with an eye icon, visible as soon as play starts.[13]

Watch towers are selectable structures but have no hit points (like mineral fields and geysers) and have only the "structure" attribute.[2]


The following section contains information from a previous version of StarCraft II which is no longer valid.

The tower was originally a protoss structure conceived by Samwise Didier. It was eventually repurposed into a xel'naga structure.[14]

The watch tower could be occupied by the overlord's Slime ability, neutralizing it.[15][16]
However, this ability was later removed.[17]


Big brother is watching.jpg Big Brother Is Watching

10 Achievement SC2 Game1.JPEG


Hold a xel'naga tower for 5 consecutive minutes in an Unranked or Ranked game.


The achievement name is a reference to George Orwell's novel, Nineteen Eighty-Four.


Heroes of the Storm[]

Heroes DevLog2.jpg

The following section contains information from Heroes of the Storm and is not canon to StarCraft continuity

Xel'naga towers appear as watchtowers on the "Warhead Junction" map of Heroes of the Storm.[18]


Towers can randomly spawn with a nameplate for the symbol of Axiom Esports, the team of the late TotalBiscuit, and of INcontroLTV, the channel of the late INcontroL.



  1. David Kim, Yeon-ho Lee, Dustin Browder, Robert Simpson. 2009-10-21. Battle Report 4. Blizzard Entertainment. Accessed 2009-10-21.
  2. 2.0 2.1 Dustin Browder, Robert Simpson, Matt Cooper, David Kim. 2008-12-19. Battle Report (1). Blizzard Entertainment. Accessed 2008-12-19.
  3. Dustin Browder, Ricardo Torres. 2008-03-12. Gamespot: Dustin Browder Starcraft 2 Interview. Blizzplanet/Gamespot. Accessed 2008-03-13.
  4. 4.0 4.1 4.2 Frank Pearce, Bob Colayco, Dave 'Fargo' Kosak. 2008-08-21. Blizzard Talks StarCraft II at Leipzig (PC). Gamespy. Accessed 2008-08-23.
  5. That particular screenshot mentioned shows off a visceral fight between Marauders and Immortals. North of the Immortal, you can also see the new model for the Xel'Naga observatory, though I'd have to say it looks much cooler animated. When it activates, it illuminates and crafts itself together to form a powered watch tower.
    Karune. 2008-11-19. screen from blizzcast 6, something strange. StraCraft II General Discussion Forum. Accessed 2008-11-19.
  6. Karune. 2007-11-12. Chat with Karune about the Screenshots. (Page 6) StarCraft II General Discussion Forum. Accessed 2007-11-12.
  7. 7.0 7.1 Xel'Naga Watch Tower only can be activated by the ground units.
    Infested Marine can activate the Xel'Naga Watch Tower but Auto-Turret can't.

    Cyrda. 2009-04-22. Do the nighthawks have true sight? StarCraft II General Discussion Forums. Accessed 2009-04-22.
  8. No, at the moment burrowed units do not activate Watch Towers. Neither do flying units but invisible units like the Dark Templar or a cloaked Ghost will activate them.
    Xordiah. 2009-03-23. Watchtower Question. StarCraft II General Discussion Forum. Accessed 2009-03-23.
  9. 9.0 9.1 9.2 The Xel'Naga Watch Towers have larger sight range than Observers, but do not offer detection. I definitely wouldn't say they are inferior, as they have crucial uses throughout the game, especially in the earlier tiers. With only a SCV/probe/drone, a player can activate a watch tower, letting you know when the enemy is coming to attack you and with that. This alone, could easily change the outcome of any early skirmish battle that happens.
    Karune. 2008-09-16. Karune, i have a question about observers. StarCraft II General Discussion Forum. Accessed 2008-09-16.
  10. The Xel'Naga Watch Towers do not grant 'detection' of cloaked units, nor does it move around like an Observer. Thus, if that pack of Dark Templars come storming into your base and you have all your probes gathered around that watch tower, it's not going to do you any good...
    Karune. 2008-09-16. Karune, i have a question about observers. StarCraft II General Discussion Forum. Accessed 2008-09-16.
  11. Does these watch towers mean the end of proxy rushes? :(

    Nope, it just means you'll have to hide them accordingly.
    Karune, Muemil. 2008-09-16. Karune, i have a question about observers. StarCraft II General Discussion Forum. Accessed 2008-09-16.
  12. Karune. 2009-01-22. StarCraft II Q&A - Batch 48. StarCraft II General Discussion Forum. Accessed 2009-01-22.
  13. Blizzard Entertainment. StarCraft II. (Activision Blizzard) (in English). 2010-07-27.
  14. 2010-2011, Starcraft 2: Watchtower. Deviantart, accessed on 2011-02-11.
  15. Burnes, Andrew. 2008-03-10. StarCraft 2 - Zerg Attack: New Screenshots, Unit Images & Unit Info! Accessed 2008-03-10.
  16. Korda, Martin. Hands-on: Martin Korda gets to grips with StarCraft II and gets the lowdown on the newly evolved Zerg. Accessed 2008-05-04.
  17. StarCraft Legacy staff. 2008-06-29. Zerg Unit Information. StarCraft Legacy. Accessed 2008-06-29.
  18. Blizzard Entertainment. Heroes of the Storm (Blizzard Entertainment) (in English). 2015-06-02.