Though around 70 percent of the earth’s surface is covered in water, much of this frontier remains a mystery to us.

But aquariums offer the special opportunity to get up close with some of the curious, colorful, and sometimes strange beings that occupy our rivers, lakes, and oceans—all while preserving the delicate balance of life in these ecosystems. Here are four of the top such institutions in America, each of which is well worth a dedicated visit.

Shedd Aquarium – Chicago

Occupying a lakefront marble structure known as Neptune’s Temple (which warrants a trip for its breathtaking architecture alone), Chicago’s tremendous aquarium positions guests face-to-face with a whopping 32,000-plus animals, including beluga whales, sturgeons, stingrays, and corals. If you’re strapped for time, you can book a guided Must See Tour to take in the aquarium’s highlights in about an hour—and get the chance to safely touch live jellyfish. However you plan your day, be sure to witness the Wild Reef, a stunning habitat populated by diverse species of sharks and fish, as well as the Abbott Oceanarium, a showcase of adorable aquatic mammals like sea lions and Pacific white-sided dolphins at play.

For more info, visit sheddaquarium.org

Monterey Bay Aquarium – California

Located on the state’s scenic Pacific oceanfront sits a magnificent aquarium that is regarded for its tremendous ecological impact. This site boasts a massive collection of over 80,000 animals and plants, such as green sea turtles, hammerhead sharks, giant clams, and the world’s largest kelp forest not found in the wild. While the Monterey Bay Aquarium isn’t the most affordable attraction—tickets for adults are $65—its nonprofit status enables it to direct these funds toward momentous conservation efforts, including recovering the threatened Pacific bluefin tuna population. This aquarium is also the originator of the well-known Seafood Watch program, which sets sustainability standards for seafood sourcing around the world.

For more info, visit montereybayaquarium.org

New England Aquarium – Boston

A noteworthy site on Boston’s iconic harbor, the New England Aquarium host thousands of species of aquatic life, from adorable African penguins to playful California sea lions to ferocious schools of piranhas. Visitors are invited to explore the depths of the Amazon rainforest, an Indo-Pacific coral reef, and other far-off ecosystems, and they can also learn about the Anderson Cabot Center for Ocean Life’s important work, which includes rehabilitating sea turtles, protecting North Atlantic right whales, and preserving other threatened aquatic life. As noted on the aquarium’s website, “We aim to inspire people to form a deeper connection to the ocean and take action to protect it.”

For more info, visit neaq.org

Tennessee Aquarium – Chattanooga

Stop by this popular waterfront landmark to view North American river otters, lake sturgeons, and other species within its two distinctive crystalline-glass buildings. You can also observe land animals such as lemurs, chameleons, and butterflies and enjoy popular films and aquatic-life documentaries in its tremendous IMAX theater. One of the most unique elements of this institution, though, is its geographically sequenced exhibits that help visitors trace the path of aquatic life from mountainous bodies of water to the ocean. For even greater immersion, book a Deeper Dives tour to witness team members caring for animal life—you can even try shark feeding!

For more info, visit tnaqua.org

Aquariums large and small are essential for not only maintaining our waterways but also educating the populace. If you live near one, consider paying it a visit or even becoming a member to ensure that its important work can continue. And if you must travel to access one, be sure to add the aforementioned eye-opening sites to your list of must-see destinations.