Avengers: Black Widow trailer finally hints at answers to Endgame MYSTERY – Here's how

Later in the Black Widow trailer, another shot of Budapest appears, showing the inside of the Keleti train station, even adorned with Hungarian flags, upon close inspection.

Judging by the trailer, it looks as though Marvel fans will finally get to find out what happened in Budapest all those years ago as Romanoff revisits her past.

With the city — and quit possibly its memories — on the agenda in the upcoming spin-off movie, which is thought to sit before Avengers: Infinity War in the timeline, could there be a chance Hawkeye might have a cameo too?

Elsewhere, the trailer also boasts a look at the woman Romanoff calls “sis”: fellow trained assassin Belova.