A must-see if you're going to visit Seattle, Pike Place is the epicenter of Seattle's business district, and a major tourist attraction. At the market center, you'll find the hustle and bustle of a multitude of vendors- everything from groceries and produce, arts and crafts, clothing, and more. You can also find the ORIGINAL Starbucks Coffee location there, as well as numerous restaurants (I recommend The Alibi Room - a quiet bar & restaurant beneath the Market (near the gum wall) with really good pizza!)
LIME E-Bikes! These things are everywhere in Seattle! Downtown Seattle is not very big, and most of it is walkable, but renting a Lime e-bike can save you a lot of time and effort getting from one place to another. You can use the Lime app, or the Uber app, to scan the QR code on the bike and ride it to your destination. They charge 47 cents per minute, so they're very affordable!
If you like marine life, definitely check out the Seattle Aquarium! I particularly recommend the After-Hours special they have! The Aquarium remains open 5:30-8:30pm for adults only...Enjoy your visit without the big crowds and noisy children, have some adult beverages, and watch the crew feed the sea otters!