At one time, 30 million tons of cargo were transported along the Detroit River, linking the city with more than 200 overseas ports. Nowadays, you can still feel the water’s tug on Belle Isle (E. Jefferson Ave. and E. Grand Blvd., www.fobi.org), accessible via the Douglas MacArthur Bridge. Belle Isle’s 985-acre urban sanctuary, stranded a half-mile out in the river, has been a public park since 1879, when the city of Detroit purchased it for a now paltry $200,000 from the heirs of a wealthy local family.

Named after the then-governor’s daughter, Isabelle Cass, it was designed in 1883 by Frederick Law Olmsted, of New York’s Central Park fame. One of Detroit’s most underrated (and often neglected) jewels, Belle Isle gets a little rowdy on summer weekends, when teenagers from surrounding neighborhoods cruise the narrow streets and pathways looking for action. Although patrolled by both mounted police and squad cars, it’s not a safe place to be at night.

On weekdays, however, it’s peaceful, especially off-season. Belle Isle is a haven for bird-watchers and for families who flock here to fish from the piers, relax on Detroit’s only swimming beach, and tour the vintage glass Anna Scripps Whitcomb Conservatory, small zoo, or intriguing Dossin Great Lakes Museum (100 Strand Dr., 313/833-5538, www.detroithistorical.org, 11 a.m.–4 p.m. Sat.–Sun., free). The museum traces the development of Great Lakes–area shipping from sailing vessels to modern freighters, many of which can still be seen from the riverfront.

Other visitors to Belle Isle come to jog, circle the island by bike, play golf, or just set up a picnic lunch under one of the gazebos and watch passing freighters. Boating enthusiasts wander around the 65-foot-tall marble Livingstone Memorial Lighthouse, which operated from 1882 to 1930, or check out the pleasure craft docked at the 1923 Detroit Yacht Club. Admission to the island is free, though there has been an ongoing debate about charging a nominal admission to help defray maintenance costs.

It isn’t the island’s first controversy. Native Americans called Belle Isle “Rattlesnake Island” because of the number of snakes. Later, hogs were brought in by 18th-century settlers to destroy the rattlers, giving rise to the name Isle au Cochon (“Hog Island” in French) until 1845, when it was rechristened Belle Isle. Throughout its long history, the island has been used both as a dueling ground and as a place of quarantine for troops, most recently during the cholera epidemic of 1932.