This story has been floating around the internet for some time, but has received renewed attention of late as it has been picked up by various local and even national media. You be the judge. . . . In footage shot at the Hollywood premiere of Charlie Chaplin's The Circus (at Grauman's Theater, 1928), there appears to be a woman passing in front of the camera who is speaking into her cell phone.
Of course, cell phones didn't exist back in 1928. That's why some have postulated that the odd-looking person seen speaking into their hand may be a time traveler. If that's so, might someone be able to contact this person and see if they could visit one of the nearby studios and pick up a lost film or two. Perhaps London After Midnight?