Marvel Studios is only two films into Phase 3 of their Marvel Cinematic Universe, but they have already been on the receiving ends of two overwhelmingly favorable reactions. Captain America: Civil War kicked off the phase and was just followed up by Doctor Strange beating expectations at the box office. To close out Phase 3, Marvel has tasked Joe and Anthony Russo to direct their third and fourth films in the universe with Avengers: Infinity War and Untitled Avengers. The former two-part event is set to be the culmination of everything before it in the MCU, and Marvel is in the final stages of pre-production.
Ahead of cameras officially rolling early next year, the Russo brothers and their crew have already started work. Josh Brolin has reported to set to start the process of playing Thanos, the threat that will bring together all corners of the MCU. Even though Thanos will have a large role in the film, so will all of the other Earth-based heroes, and now the directors are teasing one possible location that could be involved.
The Russo brothers posted a new photo on their official Facebook page of them and others scouting out a possible location that they will use in the films. The photo depicts a building, or more accurately a stairwell, that has not yet been featured in any of the Marvel films. However, thanks to the many levels of the winding staircase, some speculation has already started to wonder if this could be them implementing the Avengers Mansion.
It is impossible to say whether or not this is Avengers Mansion based on a single photo, but the idea of including this building could make sense. In each of the previous Avengers movies, the team has had a new base at some point in the film. Originally at the end of The Avengers and continuing into Avengers: Age of Ultron, the team operated out of the Avengers Tower (formerly Stark Tower) before moving to the new Avengers Facility featured at the end of Age of Ultron and again in Ant-Man and Civil War.
With these next two films set to have even more heroes than ever before, it would make sense for the team to need a larger facility at some point. However, Avengers Facility is plenty big enough for more heroes, and it seems unlikely that all of the new heroes will stay permanent members of the Avengers team that would need to be housed and trained together. Characters such as Spider-Man, Black Panther, and Doctor Strange may decide to only help out the team and then split off on their own again when Thanos is ultimately defeated.
Even if this is not the case, there is no direct connection that this is or could be part of Avengers Mansion. These two movies will be the biggest films Marvel has yet to make and with more cast members, storylines, etc., there will be a need for even more sets and buildings. This could easily be just one of many buildings featured in the film, or not included at all. Only time will tell whether or not these stairs turn out to be anything more than what they are.