The I-90 Floating Bridge is a unique bridge located in Washington State, connecting Seattle to Mercer Island. It is part of the Interstate 90 highway and spans Lake Washington. This bridge is notable for being the longest floating bridge in the world, measuring about 7,580 feet in length. Constructed in 1990, the bridge uses a series of concrete pontoons that float on the water, allowing it to adapt to changing water levels. The I-90 Floating Bridge plays a crucial role in regional transportation, facilitating the movement of thousands of vehicles daily across the lake.