Celilo Falls (Wyam, meaning "echo of falling water" or "sound of water upon the rocks," in several native languages) was a tribal fishing area on the Columbia River, just east of the Cascade Mountains, on what is today the border between the U.S. states of Oregon and Washington. The name refers to a series of cascades and waterfalls on the river, as well as to the native settlements and trading villages that existed there in various configurations for 11,000 years. Celilo was the oldest continuously inhabited community on the North American continent until 1957, when the falls and nearby settlements were submerged by the construction of The Dalles Dam. The main waterfall, known variously as Celilo Falls, The Chutes, Great Falls, or Columbia Falls, consisted of three sections: a cataract, called Horseshoe Falls or Tumwater Falls; a deep eddy, the Cul-de-Sac; and the main channel. These features were formed by the Columbia River's relentless push through basalt narrows on the final leg of its journey to the Pacific Ocean. For 11,000 years, native peoples gathered at Wyam to fish and exchange goods. They built wooden platforms out over the water and caught salmon with dipnets and long spears on poles as the fish swam up through the rapids and jumped over the falls. Historically, an estimated fifteen to twenty million salmon passed through the falls every year, making it one of the greatest fishing sites in North America.