The Octagon is distinctive in both its exterior and its interior: the outside being an octagonal central tower leading into a dome and the inside a staircase winding concentrically toward the top. In 1839, the New York Lunatic Asylum which featured the Octagon Tower was built with granite mined from the island.
It was one of the first institutions for the treatment of the mentally ill in America. The purchase of Blackwell's Island by New York City had institutional development as the goal and it was believed that the soothing, natural surroundings would be conducive to rehabilitation of all human ailments. Therefore, having bought the island in 1828, the City erected a penitentiary in 1829 and finished the Asylum a decade later.
Designed by Alexander Jackson Davis, the structure has been altered, augmented, and renovated countless times but the simplicity and beauty of the Octagon Tower's shape remains the central focus. The island Asylum was part of the great changes in treatment of the mentally ill that occurred over the late 1800s and early 1900s. Patients were acknowledged as requiring medical assistance instead of just restraint and maintenance, and rehabilitation became the objective.
Octagon Tower is now completely restored after years in the early 1900s when it was vandalized and burned twice. Two high-rise apartment wings with 500 residences extend out from the domed landmark, encircling and looking out on a private pool, playground, park complete with grills, sports fields and tennis courts.