Where Do They Start? 2029, they being the T 1000 (Robert Patrick) and a reprogrammed T 800 (Arnold Schwarzenegger).Where Do They End Up? 1991, to respectively assassinaterescue John Connor (Edward Furlong).
Biggest Culture Clash. The original audiences discovery of the T 1000s gobsmacking effects, achieved (as far as we known) without time travel.Unresolved Paradox. Skynet is founded using bits of the Terminator that it wont invent until much later.