My brother and I and friends went out to the Museum of History and Industry in South Lake Union neighborhood (yes, I was there a few weeks ago as well), grabbed a bite to eat nearby, and went on to check out the Ballard Locks (official name : Hiram M. Chittenden Locks). The locks are part of the Lake Washington Ship Canal, a large project that was started in 1911 and officially completed only in 1934. The system of locks separate the fresh water body of Lake Union that is on average 20 ft higher than the salt water of Puget Sound (depending on the tides). The locks also have a ‘fish ladder’ .. a set of boxes and weirs that allow salmon to migrate into Lake Union and Lake Washington to spawn. I see fish like salmon that do this salt water-fresh water migration, are called diadromous fish.