Castle Hill residents fear their suburb will become a "mini Manhattan", after the Hills Council revealed plans for a landmark 18-storey tower on a site bounded by Gay Street, Old Castle Hill Road and Pennant Street. The original plan allowed about 100 units on the site, which would include a mix of townhouses and apartments ranging from two to four storeys. The new plan allows for three-tiered buildings, as well as private and public open spaces. "This is a leafy, quiet, semi-rural area, it isn't made for high rises . . . it's almost as if the council idea is to turn us into another Bangkok," a resident said.