One of the ten longest bridges in the U.S. is located in the Florida Keys, and there are actually two of them: the Seven Mile bridges, of which one is the original that was built in 1938, and the second, present-day bridge was built in the early eighties (I don't know the exact date but they started building it in '79, shortly after I graduated high school.) If you've ever seen the movie True Lies, the end part with the bridge was actually filmed on a section of the original Seven Mile bridge.
My parents sometimes took us to the Keys when I was a kid, and I always tried to hold my breath as much as possible while we drove across Seven Mile. My logic was if we went over the side (and the original bridge was just a long concrete two-lane road with puny guardrails on either side, so flipping over the side seemed like a distinct possibility) that if I held my breath I wouldn't drown.
Here's a shot of the new bridge:
Last time I checked, Seven Mile ranked 8th on the longest U.S. bridge list. The funny thing about this bridge is that it isn't seven miles long. It's almost a quarter-mile short of seven miles, but I guess The Six and Three-Quarter Mile Bridge didn't have the same ring to it.