This level name is unconfirmed. If you know of the correct name, please discuss it on the talk page before renaming it.
Hidden City (unofficial name) is the thirteenth level (in the official numbering) in Keen 3. It is an optional level, located in the Secret Island. A translation of the Standard Galactic Alphabet can be found in this level in the school on top of the mountain.
This level is the one with the most Foobs in the game (20), which could earn it the name Foob City or Foob Caves. It may also be seen as a remote training facility for young Youths, as the island is not easily accessible, and the only construction it has is the Vorticon school at the top. The only Vorticons in the level are the Youth and their teachers in the school. This level has two exits, one that can be reached near the entrance, but only with the Impossible Pogo Trick, and another one near the end. It is not easy to die in this level, as besides the Vorticon Woman, the only things that kill Keen are some pools of water and a couple of stalactites and stalagmites. If Keen misses the first exit, he can easily get to the second one just by falling to the bottom. However, to get the most points, Keen should go down slowly, investigating all the winding tunnels, as it is not easy to go back up once he reaches the bottom (only using the Impossible Pogo Trick, and some hidden, dark ledges), and some parts cannot be accessed again.
This is the level with most points in the game (162,000), mainly because there are twenty-four Stuffed Toy VortiNinjas in the level.
See also List of Keen 3 levels.