This St. Louis treasure is both the country’s oldest continually operated botanical garden and a National Historic Landmark. While it’s fun to take a casual stroll through the grounds and explore the gardens independently, we recommend taking advantage of the Botanical Gardens’ various organized tours and events, many of which are geared toward families. There’s also a special Children’s Garden on site that has hands-on exhibits where kids can soak up fun facts about trees, caves, wetlands, pollination and more.