Scientists believe that about 1,000 years ago, a giant landslide from the north shore of the Columbia River blocked the Gorge and stopped the river’s flow. This natural dam created an inland sea in eastern Oregon, Washington, and into Idaho. Over time, water eroded the dam and created a natural stone bridge. Eventually, this bridge fell, creating the Cascade rapids. Local Native American legend also speaks of the creation and destruction of this natural bridge, and it is from this that the bridge received it name.