Mentioned by The Crazy Tourist
55 Best Things to Do in Seattle (Washington
"Army Corps of Engineers, the busiest set of locks in the United States allows water traffic to travel between the tidal waters Puget Sound and the Lake Washington Ship Canal. This waterway passes through Seattle’s inland freshwater lakes, via Lake Washington, Portage Bay, Lake Union and Salmon Bay, where it meets Puget Sound. The locks have permanently changed Seattle, lowering the water level on Lake Washington and Lake Union by 2.7 metres, giving rise to many miles of new land on the lakefronts."