The most well-known is likely Avengers Tower**, which was the headquarters of the Avengers in New York City. It was a skyscraper with advanced technology and served as a base of operations for the team.
Other places include:
* The Baxter Building: Headquarters of the Fantastic Four in New York City.
* Xavier's School for Gifted Youngsters: Training school for mutants run by Professor Xavier and home to the X-Men.
* The Sanctum Sanctorum: Home of Doctor Strange in Greenwich Village, New York City.
* The Raft: A maximum-security prison for supervillains.
* Stark Tower: Tony Stark's headquarters before he built Avengers Tower.
* The Triskelion: Headquarters of S.H.I.E.L.D.
So, depending on the context, you can use any of these names. For example, if you're talking about the Avengers, "Avengers Tower" would be the most accurate.