Copper is filmed in Canada, and, to mimic the iconic 'Five Points' of New York, the show runners created an entire replica in an old car factory.
Franka Potente had to cover most of her own tattoos during filming, except one of Chinese symbols, because this would have actually been fairly usual for her character at the time.
Before they began filming, show runner Tom Fontana sat all the cast down and asked them to develop and share their own back story.
Handguns used in the series are modern reproductions made by Italian firearms manufacturer Pietta.
The gun fights are shot with real guns from the 1800s, and Anastasia Griffith said that the "props guys are so excited by the guns".