In the fight scene at the end of the film "Enter the Dragon" (1973), there were over 8,000 mirrors used to help create the 'Hall of Mirrors' climax duel fight situation. In the film, Bruce Lee plays a martial-arts expert determined to help capture the narcotics dealer whose gang caused the death of his sister. Lee enters a kung fu competition in an attempt to fight his way to the dealer's headquarters. He is able to get needed results since he has the help of some friends.

Regarding the idea to use mirrors, the film's cinematographer, Gil Hubbs, said that the idea came while he and others were at lunch. They were in a restaurant that had mirrors lining the walls and ceiling. A member of the group making "Enter the Dragon" asked if filming a room with mirrors would create any challenges or aesthetic problems.

Hubbs noted in an interview that the group found: “You had to actually physically touch someone because you might be talking to the wall. Lee actually walked into a number of mirrors; we all walked into mirrors a bunch of times. We all found challenges."

In making the film, actors and camera operators couldn’t stay in the room with the mirrors for more than 15 minutes. Some of them got sick (staying in the hall of mirrors too long made some actors nauseous). Before the production could resume filming, once people became sick, breaks had to be taken.

More Info: uproxx.com