The Triskelion appears in full for the first time in the Marvel Cinematic Universe (MCU) in Captain America: Winter Soldier (dir. Anthony & Joe Russo, 2014), as the headquarters of SHIELD (the Strategic Homeland Intervention, Enforcement and Logistics Division). When the film came out in the spring of 2014, Marvel’s Agents of S.H.I.E.L.D. was wrapping up its first full season on ABC, led by agents Phil Coulson (Clark Gregg) and Melinda May (Ming-Na Wen). And Steve Rogers/Captain America (Chris Evans), having been frozen near the end of Captain America: The First Avenger (dir. Joe Johnston, 2011), only to be revived in the present by Nick Fury (Samuel L. Jackson).
Winter Soldier positions the Triskelion as the setting of Cap’s re-engagement with the problems of the modern world, established via an extended fly-by in the film’s opening that gives a specific location in Washington, DC, and show’s the building’s relation to prominent locations and monuments:
These details put SHIELD’s headquarters on Theodore Roosevelt Island, with docks/pylons facing east and the main compound oriented north/south. There seems to be one road for access, the Theodore Roosevelt Memorial Bridge (I-66) integrated into the footprint of the Triskelion, which passes from the north-east corner of Arlington National Cemetery into DC between the Kennedy Center and the Lincoln Memorial.
In Ant-Man (dir. Peyton Reed, 2015), an early flashback, set in 1989 and featuring the construction of the Triskelion, makes its geographic position on the island even clearer:
Theodore Roosevelt Island is an interesting choice, as it is mostly occupied by a national park (link), and not accessible to vehicle traffic. It also puts the Triskelion just a couple of bridges up the Potomac River from the Pentagon, one of SHIELD’s rivals in the MCU.
Winter Soldier primarily concerns itself with the emergence of the metal-armed sub-titular character, who is revealed to be a brainwashed Bucky Barnes (Sebastian Stan), controlled by the evil covert organization Hydra, who, by the end of the film, are revealed to have infiltrated SHIELD and the the Triskelion itself, including Secretary of Internal Security Alexander Pierce (Robert Redford). Thus, the Triskelion is not just a major setting, but its brutalist towers and river access are central to Hyrda’s plans (and antagonism to Cap), involving an attempt to control three attack Helicarriers, revealed by Nick Fury early in the film in under-water hangers
and that of course will emerge by the film’s climax:
However, the location is perhaps even more salient for a variety of genre-specific visual references, while simultaneously allowing for a site-specific sense of real-world proximity that runs through the film.
Winter Soldier in plot and tone overly draws on 1970s political thrillers, including The Parallax View (dir. Alan J. Pakula, 1974), Three Days of the Condor (dir. Sydney Pollock, 1975), and All the President’s Men (dir. Alan J. Pakula, 1976). The latter two of course starred Redford on the run from and investigating two different conspiracies–one fictional, the other real–and Winter Soldier trades on his presence throughout. In an early scene, Pierce and Cap sit down to discuss Cap’s commitments (with an aerial photo of the Triskelion on the wall behind them),
in Pierce’s office that overlooks the Lincoln Memorial,
before Cap leaves to contemplate his allegiances, not suspecting Redford’s character of his Hydra ties, but offset by the Watergate Hotel complex across the river.
This exchange, and an attempt to contain Cap forces him to flee over the Theodore Roosevelt Memorial Bridge (after taking out a Quinjet, giving a nice view of the signage and geography:
Cap is thus on the run for the middle of the film, before needing to return to the Triskelion, and with the help of Falcon (Anthony Mackie) and Black Widow (Scalett Johansson), to attempt to secure control of the three Helicarriers before they assassinate thousands of Hydra’s foes. This spectacular climax relies on establishing graphics that locate the Helicarriers and their targets
as well as the Helicarriers above DC’s imagined (Triskelion) and real geographies:
Before the all come crashing down, one into the Triskelion itself, in the climax:
The plot, conspiracy, and its moving parts (including the Triskelion and Helicarriers) thus mostly collapse in on themselves, with Cap, Falcon, and Black Widow taking down the Helicarriers, Fury dispatching Pierce, the Winter Solider reluctantly pulling Cap from the Potomac and onto the shore, while the Triskelion smolders:
The art book for Winter Soldier has some lovely concept art and overview images [click to enlarge].
While that’s all for the building in Winter Soldier, it could have appeared in a scene in Spider-Man: Homecoming (dir. Jon Watts, 2017), as evidenced in this deleted scene:
Finally, for a bit of the visual magic that created the Triskelion and Helicarrier fight: