At verdant Washington Park Arboretum, explore the winding pathways through woodlands, wetlands, and gardens. You can sign up for a free walking tour the first Thursday of each month to learn about special plant collections and what’s in bloom seasonally. Then see a true feat of engineering at Ballard Locks, which connects Puget Sound to Lake Union and Lake Washington. The “water elevator” built in 1917 allows vessels to move from freshwater to saltwater and vice versa, raising or lowering up to 26 feet in the process. There’s a free tour daily from May through September. Don’t miss the adjacent botanical garden and salmon ladder, where you can cheer on the fish headed upstream to spawn during the summer months. Bringing the outdoors in, the Seattle Spheres houses more than 40,000 cloud forest plants inside their radiant glass domes. Though they were built as a one-of-a-kind workspace for Amazon employees, the public can go inside the first and third Saturdays of each month, by reservation. Pro tip: Book early, it fills up fast!

At the dynamic Seattle Center campus, the Gates Foundation Discovery Center uses interactive exhibits to wrestle with how humanity can solve some of the world’s most pressing global health issues. Get a backstage look at some of the city’s most prominent performing arts venues—the Moore, Paramount, and Neptune Theatres—on one of Seattle Theatre Group’s free tours, held select Saturdays. The always-free Frye Art Museum showcases an exceptional collection of modern and contemporary works. In Pioneer Square, the engaging Klondike Gold Rush National Historical Park traces the journey of some of the prospectors who used Seattle as their launching point to strike it rich (or at least try). Nearby, throughout the week you’ll find free programmed events at Pier 62 along the dynamic Seattle waterfront—think yoga classes, dance parties, art displays, and cultural festivals.

Take note that many of the city’s museums that do normally charge admission open their doors free to the public on First Thursdays, typically staying open later on these days as well. This is also when the nation’s longest-running art walk happens, the First Thursday Art Walk in Pioneer Square.