Speaking of Eastern Promises, there’s a “prop” that Nikolai has on him, known as worry beads. In the world of Russian prisons, they’re made out of melted-down plastic lighters, and somehow Mortensen got his hands on the real thing. The worry beads in the film are exactly that.

On top of that, Mortensen actually spent five days in the Ural Mountain region of Siberia, learned his lines in English, Russian, and Ukrainian simultaneously (he wasn’t required or asked to do that), and read as many books as he could on Russian prisons and gangs. All for one movie, and he hasn’t played a Russian gangster since.