Lightning struck the clock tower at precisely 10:04 p.m. Sending the necessary 1.21 gigawatts into the time vehicle, which vanished in a brilliant flash of light leaving a pair of fire trails behind.
10 seconds sound clip from the Back to the Future Part III movie soundboard.
You can hear this line at 00:05:35.945 in the DVD version of the movie.
Quote context
[...]
- Date. Sunday, November 13, 1955.7:01 a.m.
- Last night's time travel experiment was apparently a complete success.
- Indeed, I now recall that moments after the time vehicle disappeared into the future...
- I saw a vision of Marty saying he had come back from the future.
- Undoubtedly, this was some sort of residual image...
- Doc.
[...]