New England Aquarium

The New England Aquarium sits on Central Wharf overlooking Boston Harbor, and its centrepiece — the Giant Ocean Tank, a 200,000-gallon four-story cylinder of seawater containing sea turtles, sharks, rays, and hundreds of tropical fish — is one of the most mesmerising exhibits in any American aquarium. You enter at the base of the tank and walk a spiral ramp around it to the top, watching the marine life at progressively greater depths, and by the time you reach the summit you've spent 20 minutes in a state of oceanic hypnosis.

Myrtle, the aquarium's green sea turtle, has been the star of the Giant Ocean Tank since 1970 and is one of the longest-resident animals in any American aquarium. She weighs over 500 pounds, has her own social media following, and swims laps around the tank with a serenity that suggests she's come to terms with her celebrity. The daily diver feeding presentations — where aquarists enter the tank in scuba gear and hand-feed the animals while narrating over a microphone — are consistently the best-attended show.

The outdoor seal exhibit on the harbour-side terrace is free to visit without aquarium admission and features northern fur seals and harbour seals who seem to enjoy performing for the lunchtime crowds from the nearby Financial District. The aquarium also runs whale-watching tours from its dock — a three-hour boat trip to Stellwagen Bank that offers some of the best whale watching on the East Coast, with humpbacks, fin whales, and the occasional right whale.