The National Aquarium opened its 10,000-square-foot Harbor Wetlands exhibit this week, creating a first-of-its-kind hybrid experience where native animals can flourish in a free, outdoor, hands-on classroom and park setting.

“It is the product of about 14 years of work that the National Aquarium has done,” said Charmaine Dahlenburg, the director of field conservation at the Aquarium. “The thing about what you're going to see when you come down here, is we're just not sure. Any animal that wants to come on is welcome to. We don’t stock it with any kind of exhibit animals. This is a habitat for the animals that live in Baltimore City, so you never know what you're going to see out here.”

So far, the exhibit has attracted a slew of native animals including mallards, herons, diamondback terrapins and even two river otters.

The exhibit mimics the Chesapeake Bay tidal marsh and is situated between piers three and four in Baltimore’s Inner Harbor.

It’s completely free to guests while the Aquarium is open.

In total it cost about $14 million to build the exhibit, which was mostly paid for through donations.

The aquarium planted 32,000 native shrubs and marsh grasses to build the area.

Those plants sit on recycled plastic matting. The grasses will create microhabitats for native species and the roots will suck up nitrates that are bad for the harbor.

Water is also constantly circulating through small man-made streams that are pushed along by compressed air coming from ceramic airstones at the bottom of the marsh.

The bubbles raise the dissolved oxygen levels in the water benefiting the animals and harbor.

The Aquarium applied for three patents while building the exhibit, mostly for that system.

“Natural habitat restoration is a key part of our all-hands-on-deck strategy to improve the health of the Chesapeake Bay. That’s why I’ve fought to support the National Aquarium’s efforts to create this floating wetland right in the heart of downtown Baltimore,” said Sen. Chris Van Hollen (D-Md.), who secured some funding for the exhibit. “Not only will this innovative approach bring Bay wildlife back to the Inner Harbor; it will also serve as a living educational resource, helping strengthen the culture of shared responsibility for protecting our treasured Bay for generations to come.”

There are walkways for humans that cut through the marsh with informational panels about the exhibit, making it a hands-on classroom as well.

The Aquarium is making the exhibit interactive.

Along with cameras set up to catch wildlife enjoying the marsh, there are places to set your phone to try and snap some pictures yourself.

The Aquarium is encouraging people to send in their wildlife photos and post them on social media as more people visit the new wetlands exhibit.