World Trade Center 7, funnily enough. The idea of some government goons being like "I'm just worried this isn't dramatic enough, Americans just won't be upset enough by two towers going down, we probably need to randomly knock down a tower that nobody knows to really push them into a frenzy" is very curious to me.
Truthers think the collapse of WTC 7 is suspicious because it housed several government tenants: a clandestine CIA office, the New York branch of the U.S. Secret Service, the Securities and Exchange Commission, and the NYC Office of Emergency Management. In some theories, WTC 7 was the operational center for the controlled demolition of the Twin Towers (meaning that it also had to be collapsed in order to destroy the evidence, of course!)
