re: A new meaning for freeway overpasses
That's nothing. There are a few in the world where the canal bridge is a swing bridge and opens to let ships through underneath, with gates that close to keep the water in the swinging segment.
Examples include the barton Swing Aqueduct over the Manchester Ship Canal in the UK
here
here
and here
I have had the pleasure of sailing a narrow boat across this bridge and watching it swing, as well as many of the other wonders of the English canals.
If you're looking for excitement, follow the last link to the "Falkirk Wheel" !!!