Monument is just outside the park entrance. The square Grand Army Plaza is on the southeastern corner, at the junction with Fifth Avenue and 59th Street. Its largest feature is the Pulitzer Fountain, which was completed in 1916 along with the plaza itself. The plaza contains the William Tecumseh Sherman statue, dedicated in 1903. Duke Ellington Circle, at the northeastern corner, forms the junction between Fifth Avenue and Central Park North/110th Street. It contains the Duke Ellington Memorial, dedicated in 1997. Duke Ellington Circle is adjacent to the Pioneers' Gate. Frederick Douglass Circle is on the northwestern corner, at the junction with Central Park West/Eighth Avenue and Central Park North/110th Street. It was named for Douglass in 1950. The center of the circle contains a memorial to Frederick Douglass, dedicated in 2011. Structures The Dana Discovery Center was built in 1993 at the northeast section of the park, on the north shore of the Harlem Meer. Blockhouse No. 1, the oldest extant structure within Central Park, and built before the park's creation, sits in the northwest section of the park. It was erected as part of Fort Clinton during the War of 1812. The Blockhouse is near McGowan's Pass, rocky outcroppings that also once contained Fort Fish and Nutter's Battery. The Lasker Rink, a skating rink and swimming pool facility, formerly occupied the southwest corner of the Harlem Meer. The Conservatory Garden, the park's only formal garden, is entered through the Vanderbilt Gate at Fifth Avenue and 105th Street. The North Meadow Recreation Center, tennis courts, and the East Meadow, sit between the Loch to the north and the reservoir to the south. The North Woods takes up the rest of the northern third of the park. The areas in the northern section of the park were developed later than the southern section and are not as heavily used, so there are several unnamed features. The park's northern portion was intended as the "natural section" in contrast to the landscaped "pastoral section" to the south. The area between the 86th and 96th Street transverses is mostly occupied by the Onassis Reservoir. Directly south of the Reservoir is the Great Lawn and Turtle Pond. The Lawn is bordered by the Metropolitan Museum of Art to the east, Turtle Pond to the south, and Summit Rock to the west. Summit Rock, the highest point in Central Park at , abuts Diana Ross