Washington State History Museum: Displays a fascinating collection of artifacts from the state's history. You'll find exhibits that feature Native American art and people, early European settlement, state industry and labor, and geology.
Pt. Defiance Zoo & Aquarium: Features animals from the Pacific Northwest and around the world. Their Rocky Shores exhibit includes sea otters, tufted puffins, and clever Beluga Whales. In the Asia Forest Sanctuary, you can view Sumatran tigers, white-cheeked gibbons, and Asian elephants. In other exhibits, you'll see sharks, sea horses, jelly fish, and octupi.
W.W. Seymour Botanical Conservatory: The historic glass conservatory, with a distinctive twelve-sided central dome. Exotic tropical plants and floral displays can all be seen in the lovely structure, where 3,500 panes of glass make up the dome and wings of the Conservatory.
Wild Waves & Enchanted Village: Is both a water park and an amusement park. Visitors can enjoy a huge wooden roller coaster, a variety of water-themed thrill rides, a 1906 antique carrousel, and kiddie rides. Food, games, and entertainment are also part of the fun.
Museum of Glass: Is the only American museum that features contemporary glass art; there are just three in the world with such a focus. You can watch glass artists at work in the hot shop amphitheater located in the metal-clad cone attached to the museum.
Source: http://www.tripadvisor.co/Attraction