Corrected entry: During the scene where Blondie and Tuco are wiring the bridge with explosives, Tuco suggests they tell each other their part of the secret. As Blondie is replying, you can see a car drive by in the background. The movie takes place in the 1860s.
Bishop73
27th Apr 2003
The Good, the Bad and the Ugly (1966)
Correction: I have watched this scene several times and what you say never happens, there is NO car driving by in the background.
When Tuco says "you go first", there's a car in the far background driving down a road. At first the trees are kind of blocking it, but then there's a clearing and the car is more visible. Look to the right of Clint Eastwood's hat.
Correction: Yeah I see it now too. In the forest.