10. SR 520 Floating Bridge (Washington)
Estimated Cost: $4.5 billion
The SR 520 Floating Bridge located in Seattle is undoubtedly one of America’s biggest and most popular construction projects. It is known as the world’s longest bridge and is also famous for its strong capacity of carrying heavy cars and even trains. Not only did it make headlines because of how much it costs, but it is also known for its beauty.
