Opened nearly 55 years ago, the 3.5 mile long Hampton Roads (Virginia) Bridge-Tunnel is an amazing four-lane bridge/tunnel that goes across and under the main shipping channels for Hampton Roads harbor. As you would expect, it looks pretty awesome in Google Earth.
It’d be cool to see more of it in 3D, especially the underwater tunnel, but it’s quite impressive with just the satellite imagery to view. As most bridges do, it replaced a ferry route that had been active prior to its construction. When it opened in 1958, it had an average of 6,000 vehicles that used it each day. The average is now 66,000/day, with spikes over 100,000 during tourist seasons.
You can read more about the Bridge-Tunnel on their Wikipedia page, or see it for yourself in Google Earth with this KML file.