The World's Strangest Bridges: Evergreen Point Floating Bridge

Background: This floating bridge, which was completed in 1966, carries State Route 520 from Seattle to Medina, Washington. At 1.4 miles long, it has one of the longest floating spans in the world.

Why It's Innovative: Because Lake Washington can be more than 200 feet deep, building a suspension bridge across it was not a viable option in the 1960s. The floating design, which relies on concrete pontoons that are anchored by underwater weights, was the perfect solution. In its more than 40 years of existence, the Evergreen Point Floating Bridge has been battered by high-speed winds and even withstood a barge crashing into it. However, these abuses, along with the bridge's vulnerability to earthquakes, have forced the Washington Department of Transportation to launch a project aimed at replacing the structure.