South of the I-490 bridge, the Valley widens to one and one-half miles. This grand scale corresponds to the large steel making operations located here; this district's gritty and raw character is synonymous with Cleveland's industrial past. In its transformation to an engine for Cleveland's economy, many of the Valley's natural features such as the the hillsides, Morgan Run, Burk Branch, and the Cuyahoga River itself were altered, removed or covered to a great extent. Much of Cleveland's ethnic heritage and America's industrial revolution emanates from here.