Here's an ideal itinerary for 3 days in Seattle:

Day 1:

• Start your day with a visit to Pike Place Market, one of the most iconic attractions in Seattle. You can grab breakfast at one of the many cafes or bakeries in the market and explore the stalls selling fresh produce, seafood, flowers, and handmade crafts.
• After exploring the market, head to the Space Needle, which offers stunning views of the city from its observation deck. You can also visit the Chihuly Garden and Glass exhibit located next to the Space Needle, which showcases the work of renowned glass artist Dale Chihuly.
• In the afternoon, take a stroll through the Olympic Sculpture Park, which features large-scale sculptures and installations by local and international artists. The park also offers beautiful views of Elliott Bay and the Olympic Mountains.
• End your day with dinner at one of Seattle's many excellent restaurants. Some popular options include Canlis, The Walrus and the Carpenter, and Salare.

Day 2:

• Start your day with a visit to the Museum of Pop Culture (MoPOP), which celebrates the history and culture of popular music, science fiction, and pop art. The museum features interactive exhibits, rare artifacts, and memorabilia from some of the biggest names in music and entertainment.
• After the museum, head to the nearby Seattle Center, which is home to several other attractions, including the Pacific Science Center, the Seattle Children's Museum, and the Bill & Melinda Gates Foundation Discovery Center.
• In the afternoon, take a ferry ride to Bainbridge Island, which offers stunning views of the Puget Sound and the Seattle skyline. Once on the island, you can explore the charming downtown area, visit the Bainbridge Island Museum of Art, or go for a hike in one of the island's many parks.
• End your day with dinner at one of the island's many excellent restaurants, such as Hitchcock or Cafe Nola.

Day 3:

• Start your day with a visit to the Seattle Aquarium, which features a wide variety of marine life from the Pacific Northwest and beyond. You can watch sea otters play, touch starfish and sea anemones in the tide pools, and see sharks and other fish up close.
• After the aquarium, head to Pioneer Square, which is one of Seattle's oldest neighborhoods and features many historic buildings and landmarks. You can take a guided tour of the neighborhood, visit the Klondike Gold Rush National Historical Park, or explore the many art galleries and shops in the area.
• In the afternoon, take a walk along the waterfront and enjoy views of Elliott Bay and the Olympic Mountains. You can also visit the Seattle Great Wheel, which offers stunning views of the city from its enclosed gondolas.
• End your day with dinner at one of the many excellent seafood restaurants in the area, such as Elliott's Oyster House or The Crab Pot.