The past two decades have seen the dozens of islands scattered across Boston Harbor transformed from barely noticed dots on the horizon to one of the city’s most popular attractions. The Boston Harbor Island National Recreation Area, established in 1996, has propelled them into prominence, with ferries carrying day-trippers and overnight campers from downtown Boston, Hingham, and Hull to eight of the islands (19 more are accessible by private boat or charter excursions). Most visitors head to Georges Island, home of the Civil War–era Fort Warren, or the beaches and hiking trails of Spectacle Island, the one closest to downtown Boston. (Don’t skip the concession stands here: The food is from James Beard Award–winning Boston chef Barbara Lynch.) You can also camp on Peddocks, Grape, and Bumpkin islands, or take a tour to Little Brewster Island to witness the 300-year-old Boston Light, the nation’s oldest lighthouse.