Mulder tells the Captain that the world in 1998 is at peace. He says that there's a little trouble at the White House, but that it will "blow over, so to speak." Mulder is referencing the Monica Lewinsky scandal.
The episode is comprised of six very long, continuous shots, called long takes. Chris Carter intended this as an homage to the Alfred Hitchcock thriller Rope (1948), which used a similar technique.
Many of the costumes used in this episode were costumes from Titanic (1997) borrowed by the Fox wardrobe department.
Most of the Nazis are played by real Germans in order to sound more authentic when they speak. Skinner, as well, hasn't any problem speaking German due to his spending some time in Germany when he was a child.
Toward the end of the sequence with Scully in the beginning trying to find information on where Mulder is, she is running out of Fowley and Spender's office and going around the corner toward the elevator. She slips and almost falls. It's quite obvious; One can hear her slip and also see Gillian Anderson's arm shoot out to catch herself. She's quite lucky that she didn't fall because if she had, they would have had to start back at the very beginning of the scene and do it all over again because they filmed the entire scene in real time.