The Back Bay Fens marshland gave this section its name, but two quirky institutions give it its character: Fenway Park, which in 2004 saw the triumphant reversal of an 86-year drought for Boston's beloved Red Sox, and the Isabella Stewart Gardner Museum, the legacy of a high-living Brahmin who attended a concert at Symphony Hall in 1912 wearing a headband that read "Oh, You Red Sox." Not far from the Gardner is another major cultural magnet: the Museum of Fine Arts. Kenmore Square, a favorite haunt for Boston University students, adds a bit of funky flavor to the mix.

After the outsize job of filling in the bay had been completed, it would have been small trouble to obliterate the Fens with gravel and march row houses straight through to Brookline. But the planners, deciding that enough pavement had been laid between here and the Public Garden, hired vaunted landscape architect Frederick Law Olmsted to turn the Fens into a park. Olmsted applied his genius for heightening natural effects while subtly manicuring their surroundings; today the Fens park consists of irregularly shaped reed-bound pools surrounded by broad meadows, trees, and flower gardens.

The Fens marks the beginning of Boston's Emerald Necklace, a loosely connected chain of parks designed by Olmsted that extends along the Fenway, Riverway, and Jamaicaway to Jamaica Pond, the Arnold Arboretum, and Franklin Park. Farther off, at the Boston–Milton line, the Blue Hills Reservation offers some of the Boston area's best hiking, scenic views, and even a ski lift.