How did the Roman destruction of the temple differ from Nebuchadnezzar's?
Nebuchadnezzar's destruction of the temple was primarily by fire, consuming its cedar wood like a matchbox. The Roman destruction, though also using fire, went further by literally dismantling the temple rock by rock and stone by stone, driven by reports of gold hidden between the building blocks. This fulfilled Jesus' prophecy that not one stone would be left upon another.
Les explains that when Nebuchadnezzar destroyed the temple, he did it by fire. Because the temple was predominantly cedar wood, it burned like a matchbox. The Romans, even though they used a lot of fire, did not just destroy it with fire; they literally dismantled that temple rock by rock and stone by stone. Les notes there are legendary stories about why they did this: some Roman soldiers had heard there was tons of gold hidden between the building blocks of the temple, so in order to go after that gold, they took it down stone by stone. Les says this is exactly what Jesus was talking about in prophetic utterance when He said not one stone would be left upon another.