Los Angeles Subway

The Los Angeles Subway is an underground mass transit transport network in that city. It is also known as the 'metro' or 'underground'. Due to the amount of people in the subway and often confined spaces, it is an ideal place for a terrorist attack to take place due to a high number of casualties.

24: The Game
During 24: The Game, CTU is given an anonymous tip off to a Sarin gas attack on the subway system. Tony Almeida lead a team to a subway station where they were attacked by several terrorists who took some members of the public hostage. Almeida and his team were able to secure the station and apprehend Eddie Cain.

The attack was used as a diversion so that terrorists could set off an Electromagnetic Pulse inside CTU Los Angeles and attack the building.

Day 3
During Day 3, Arthur Rabens was directed to release the Cordilla virus in the subway. Steven Saunders gave CTU a lead which allowed them to track the virus to a subway station because of a tracker placed on it. When Rabens became suspicious, he dumped the tracker and moved into the subway.

CTU blocked all the station's exits and started to try and identify Rabens who escaped and stabbed two police officers. He then attempted to release the virus in a nearby middle school.