In 1973, a groundskeeper was laying the chalk, for the stadium's baseball field, when Magneto appeared, wearing his helmet and a new costume. The groundskeeper asked Magneto if he could help him, and the mutant replied with "No, you can't".
Then, using his powers, Magneto ripped the entire stadium off its foundations, and levitated it across Washington, and towards the White House. He then set the stadium around the White House as a barrier, in order to prevent any interference with his plot to assassinate the President, his Cabinet and the humans behind the Sentinel program. The stadium sustained partial damage. Several Sentinels were also positioned around the roof of the stadium, to prevent the police from interfering.
At the end of the film, a newspaper announces that the Stadium is to begin reconstruction.