A Seattle must for fish-throwing, delicious food, and gorgeous flowers. The food tours of the market are great if you have time, and definitely be sure to stop by Piroshky Piroshky, Beecher's Cheese, Pike Place Chowder, and Rachel's Ginger Beer for local bites.
Fun fact: After the Great Seattle Fire of 1889, the streets had to be rebuilt 1-2 levels higher, leaving the original Seattle streets and storefronts underground. The Underground Tour is a fun opportunity to explore the old underground with comedic anecdotes.
The Seattle Dog is smothered with cream cheese and grilled veggies. Don't knock it 'til you try it. It's delicious.