Touch of Evil – opening shot by Orson Welles

This famous opening to Orson Welles classic film noir Touch of Evil (1958) employs a long tracking shot of Mexican police detective Mike Vargas (Charlton Heston) and his new bride Susie Vargas (Janet Leigh) as they cross the border from Mexico into the United States.  Instead of using cuts, the camera moves and tracks multiple scenes of action — the planting of the bomb, Mike and Susie walking the bustling streets of the border town, the couple in the car who are also stopped at the border.  The camera’s mobility and fluidity contrasts with the border itself, where people must stop to be processed before entering.  The viewer learns some important parts of the backstory when Mike and Susie talk to the border patrol agents: Mike and Susie are recently married, and Mike has recently solved a case involving the Grandi crime family, which he claims isn’t quite finished yet.  Once Mike and Susie cross the border, the white car explodes and we see the first cut of the film: a reaction shot to the explosion.

IMDB