Downtown Brooklyn is the third largest central business district in New York City, and is located in the northwestern section of the borough of Brooklyn. The neighborhood is known for its office and residential buildings, such as the Williamsburgh Savings Bank Tower and the MetroTech Center office complex. Since the rezoning of Downtown Brooklyn in 2004, the area has been undergoing a transformation, with $9 billion of private investment and $300 million in public improvements underway.