Washington DC - One of the most-visited cities in the U.S., our nation's capital houses a trove of postcard-worthy monuments. The White House and the Lincoln Memorial are here, as well as a variety of walkable neighborhoods. Plus, budget-minded travelers can take advantage of free attractions, like the Smithsonian museums.
Seattle Center (yes this is a map; too many places for a proper photo). I love, love-love-LOVE Seattle Center. You've got the giant fountain, the Needle, EMP, the monorail, the Children's Museum, etc. Can have a very fun day there.