The John Hancock Center, located at 175 East Delaware Place, was erected in 1969. The 100-story high-rise holds 700+ condominiums. It is Chicago's second highest residential skyscraper and the third tallest in the United States. The John Hancock Building is part of the Gold Coast neighborhood on the city's North Side. The building's construction was led by architect Wallace Harrison Eisenmann with architectural design by Bertrand Goldberg. The general contractor was William Miller and Associates. The site preparation and excavation were done by McDonough Construction Company at a cost of $1.5 million. The concrete for the foundation was supplied by Carter Concrete Products, while the steel was supplied by INA Iron Works. The building's roof is made of terra cotta tiles manufactured by Crown Terracotta of Canada. The heating, ventilation, and air-conditioning system uses R-134 refrigerant gas. The building has 493 residential units from studios to three-bedroom apartments. It also has a fitness center, laundry room, outdoor pool, sauna, and tennis court on its 28th floor roof deck. The building's annual tax bill is $750,000. Construction on the John Hancock Building began in October 1968 and it was completed in April 1969. At the time it was built, it was the most expensive single structure ever sold in Illinois (approx. $15 million).