One of the coolest things about Seattle is the ability to take a boat from Union Lake, which is several meters above sea level and make your way to the Pacific Ocean via the Chittenden Locks. I have done this on a private sailboat, and most recently, an Argosy tour.
We took a bus from the wharf where we were led on the ship. After a guided cruise through Union Lake where you can see the famous houseboats, we pulled into the sleeve of the first lock, along with some smaller boats, and yes, a kayak. it is one of those things that makes you wish you were an engineer because it is so cool (okay maybe not but almost).
You enter the lock at lake level and a sealed gate closes behind you, the lock starts to slowly release water to allow the boat to gradually lower to the level of the water below, the gate in front of you opens up and you sail out,while looking up at the lake behind you.