The Ballard Locks celebrated 100 years on Tuesday with a ceremony to commemorate the anniversary.
"Seattle in 1917 was going through unprecedented changes," Mayor Ed Murray said at the event Tuesday. "The Ballard Locks were the final piece of an ambitious project."
Crews created the locks to support the export of timber, coal, and other heavy industry on Lake Union and Lake Washington, an Army news release said.
"The Ballard Locks have opened doors to economic and recreational opportunities—opportunities that would not have been possible without a functioning and strong federal government," Murray said.
The Hiram M. Chittenden Locks were completed in 1917, but were proposed more than 100 years prior to that. Feasibility studies and route configuration took more than a century.
"The Ballard Locks are the most heavily-used Locks in the entire United States, with more than 40,000 transits and over one million tons of freight moving through every year," Rep. Pramila Jayapal said at the ceremony, noting the high amount of visitors annually.
Murray said hundreds of people visit the Locks every year. Original funding for the Locks was $2.3 million, which had to be approved by Congress.
Two Navy planes flew over the celebration Tuesday, resembling one of Boeing's earliest airplanes, a biplane, which hovered over the ceremony 100 years ago.