Trivia: It seems like a mistake, but it really isn't: Director Nicholas Meyer, in his DVD audio commentary, points out that the time machine should not have stayed in London and rightfully did belong where it ended up - in a museum in San Francisco. This is plausible not because of alternate dimensions or time zones, he explains, but because the machine was crated up and shipped there by museum curators after H.G. Wells' death/disappearance.
Trivia: In the country where the film was made, extras are not hired. The people in the background are just normal people. Watch the background during the scene where the young couple is talking in front of a subway staircase and you will see a boy flipping off the camera.