Fenway Park adjacent to engineered Back Bay Fens

Fenway Park borders the Back Bay Fens, part of Frederick Law Olmsted's Emerald Necklace, which was constructed in the late 19th century to convert tidal marshes and flood-prone land into an engineered park and drainage system. The Fens are an artificial salt-marsh landscape created by repeated engineering interventions that altered preexisting tidal and riverine geography. Fenway Park's site and nearby road and drainage layouts reflect those historic landscape modifications.