Baalbek itself is a mysterious ruin, and one which we could write about all day. For now, though, we're just going to focus on the trilithion, which forms part of the Temple of Jupiter. The trio of stones each weigh a back-breaking 800 tons.
The temple is 21 feet above the courtyard, and 40 feet above the land that surrounds it. There's no way in the world that the stones should have been moveable; the quarry they came from is downhill, and we'd have a hard job lifting them using modern technology.