The Green-Wood Cemetery
"Green-Wood Cemetery"..."is the largest and among the most influential of early American rural cemeteries, carefully sited with dramatic views of the city and harbor below. Established in 1838, Green-Wood has the most extensive and intact landscape created following the principles of Andrew Jackson Downing, the most prominent landscape architect of the antebellum period. It is outstanding for its cohesive, picturesque character, integrated Gothic Revival architecture, and high integrity."
A nice article on what to see and where to go in the UK Times: