The first pontoon for the new SR 520 floating bridge made its way through the Ballard Locks Saturday night.
The pontoon was towed 260 nautical miles from Grays Harbor, where it was built. The pontoon is longer than a football field and weighs about 11,000 tons.
The next pontoon will be brought through the locks on Monday night.
The new 520 bridge will use a total of 77 pontoons - 33 are being built in Aberdeen and 44 in Tacoma.