Atlantic harbor seal exhibit on the front of the main building and its five residents can be viewed for free and at any hour of the day, without entering the building. The New Balance Foundation Marine Mammal Center on the rear of the building can also be viewed from the outside (from the Harborwalk), and is home to a small colony of three California sea lions and one northern fur seal. Penguins The base of the Giant Ocean Tank sits in a tray of saltwater containing a habitat for penguins, including Africans and southern rockhoppers. The penguins live on several artificial rock islands in the exhibit and can be viewed from the spiral walkway, the areas around the perimeter of the tray, and every gallery. Galleries Four levels of smaller exhibits, open to the atrium and accessible via either the spiral or a separate series of ramps, surround the Giant Ocean Tank and penguin habitat. The Tropical Gallery features live corals and hundreds of warm-water fishes, including a floor-to-ceiling, Indo-Pacific coral reef exhibit. The Temperate Gallery features goliath groupers, lungfish, weedy seadragons, and sea jellies. The Freshwater Gallery is divided between freshwater aquatic habitats in the Amazon, including red-bellied piranhas, poison dart frogs, a green anaconda, and an electric eel, and the Connecticut River Valley, including brook trout and Atlantic salmon. The Northern Waters Gallery contrasts marine habitats in New England, primarily the Stellwagen Bank National Marine Sanctuary, and the Olympic Coast National Marine Sanctuary in the Pacific Northwest. Species exhibited include shorebirds, colorful American lobsters, and a giant Pacific octopus. Additionally, the Yawkey Coral Reef Center at the top of the Giant Ocean Tank sheds light on smaller-scale habitats in Caribbean waters, including dwarf seahorses and garden eels. Shark and Ray Touch Tank In 2011, the Trust Family Foundation Shark and Ray Touch Tank became a permanent exhibit in the aquarium's West Wing. Guests can interact with multiple species of stingray and shark, including leopard whiprays and brown-banded bamboo sharks, in a naturalistic mangrove habitat. The lower level of the West Wing houses the current special exhibit, the Science of Sharks, which explores shark anatomy, reproduction, and diversity. Themes The aquarium has periodically featured temporary themed educational programming, often to highlight certain animals in the aquarium's collection. Penguin Power Shining a spotlight on the aquarium's penguins in 2010, Penguin Power was designed to show off the natural abilities of