A Tripod City was a domed structure of the Masters designed to host a city inside while maintaining conditions similar to those found on Trion. There were three Tripod cities: one in Europe, Middle America, and Asia. Humans referred to the cities as "City of Gold and Lead".
Three cities were built by Masters right after the Tripod Invasion. Presumably, they used human workforce to complete the construction. The cities served as places of residence for the Masters, where the light gravity of Earth and the alien atmosphere wouldn't bother them.
At some point, the Masters began selecting human slaves through sporting competitions who they brought into their cities to work for them. To capped people, it was considered a great honor to be chosen to serve in the cities.
After the human resistance had gained strength and information, it sent teams to each city to destroy them. The European and Asian cities were successfully destroyed, but the American one held off until it was bombed later by a new wave of resistant fighters.
The cities were constructed from an unknown material. Most of the outer surface was covered with a partly translucent green dome that kept the green air of the Masters inside. There were large gates that allowed Tripods to enter and leave the city. Inside the cities were pyramid-shaped buildings serving different purposes.
The cities were built over rivers to allow the Masters to use the water inside the city. Water was purified before it entered the city for the Masters' use. The waste water that exited the city continued down the river sometimes containing alien debris and was apparently poisonous because nothing grew next to the river for a mile downstream.
At the center of each city was a Pool of Fire, that served as the source of energy for the entire city. In the TV series, it is explained that these pools were built atop nuclear reactors built by humans before the Tripod Invasion.
- The name "City of Gold and Lead" refers to the golden surface of the cities and the increased gravity inside of them.
- Chateau Ricordeau, France: August, 2089 AD
- The White Mountains: November, 2089 AD (Mentioned only)
- The White Mountains: 2090 AD (Mentioned only)
- Travel (Mentioned only)
- Will Is Arrested (Mentioned only)
- Help From Friends
- City of Gold
- Will Is Made a Slave
- Hunt for Eloise
- The City of Gold
- Blessings of the Cognosc
- The Cognosc Departs
- Escape From the City of Gold
- The Forest of Death (Mentioned only)