Roosevelt Island is a narrow, 147-acre island of roughly 12,000 residents in the East River between Queens and Manhattan. It is part of the borough of Manhattan. Since 1976, an aerial tramway has ferried passengers between Roosevelt Island to the Upper East Side. A subway connection opened in 1989. Until 1971, Roosevelt Island was called Welfare Island because of hospitals, prisons, mental asylums and government-subsidized housing developments located there. Cornell University is developing a satellite campus at the southern end of the island. Over the next 25 years, the university is planning to build a 2 million-square-foot science campus, populated by thousands of students and engineering and technology professionals. A New York City developer, the Related Companies, has built several upscale condominiums and rental buildings on the island, including Riverwalk Place and Riverwalk Crossing. Another developer, Becker + Becker, completed the 500-unit rental Octagon on Main Street. Residents enter the building through a lobby that was previously part of a 19th-century lunatic asylum.