The Sony Tower, formerly the AT&T Building, is a 647 feet (197 m) tall, 37-story highrise skyscraper located at 550 Madison Avenue between 55th Street and 56th Street in the New York City borough of Manhattan. It was designed by architect Philip Johnson and partner John Burgee, and was constructed in 1984. It became immediately controversial for its ornamental top (sometimes mocked as "Chippendale", after the open pediments characteristic of the famous English designer's bookcases and other cabinetry), but enjoyed for its spectacular arched entranceway, measuring about seven stories in height. With these ornamental additions, the building challenged architectural modernism's demand for stark functionalism and purely efficient design. It is therefore considered by many critics to be a prime example of postmodern architecture.
In October 1978, AT&T was granted permission to add 81,928 square feet (7,611.4 m2), the equivalent of some four floors of space on its proposed building, in exchange for agreeing to provide open public space and a three-story communications museum. The firm was granted an additional 43,000 square feet (4,000 m2), about two floor's worth, as a bonus for creating a 14,000-square-foot (1,300 m2) covered arcade along Madison Avenue that would include seating and retail kiosks.
In 1982, with the Bell System divestiture set to take effect on January 1, 1984, AT&T decided to seek a tenant to lease 300,000 square feet (28,000 m2) of space on the 7th through 25th floors, nearly half the space in the building, and was seeking rents of as much as $60 per square foot. The company had expected to relocate as many as 1,500 employees, most who had been located at the company's old headquarters at 195 Broadway, but the impending divestiture meant it would only be moving 600 employees into 550 Madison, with others being moved to another facility in Basking Ridge, New Jersey.
Spirit of Communication, a 20,000 pounds (9,100 kg) bronze statue that had stood for 64 years on the top of AT&T's previous headquarters building at 195 Broadway, was disassembled and relocated to the lobby of 550 Madison in 1983. The 22-foot (6.7 m) tall figure, modeled in 1916 by American sculptor Evelyn Beatrice Longman, is holding bolts of electricity clutched in one arm reaching towards the sky and has coils of cable wound around the statue's torso. After AT&T moved out of the building, the statue was relocated to a spot outside of its Basking Ridge operational headquarters in 1992.
In 1984, the company indicated that it would not build the museum that it had originally committed to build in exchange for bonus zoning. The change of heart came as part of plans following the court-ordered divestiture of the Regional Bell Operating Companies and the reduced presence it expected to have at the building. In the face of firm opposition from the city, AT&T acquiesced to construction of a three-story exhibition space in an annex located adjoining the pedestrian walkway behind the building.
AT&T had been granted a tax break of $42 million, under the condition that the company would keep its headquarters at 550 Madison Avenue and not rent out the space to other tenants. Having decreased in size substantially, AT&T signed a 20-year lease agreement on 550 Madison with Sony and relocated its headquarters to 32 Sixth Avenue, between Walker and Lispenard Streets. Sony was granted an option to purchase the building. AT&T returned $14.5 million to New York City to compensate it for tax abatements made as part of a 1987 renegotiation.
In 1992, Sony submitted plans that required approval by the New York City Planning Commission, in which it would take some of the open space in the building's atrium that had been used to obtain approval for additional floors on top of the building and convert those areas into retail space. In exchange, the company would expand the glass-enclosed pedestrian walkway with the addition of planters and public seating. Sony expected that the proposed conversion of the 8,727 square feet (810.8 m2) of public space could be converted into stores that could be leased at rates that The New York Times estimated could approach $200 per square foot. The company noted that the space was underutilized as a public amenity because it was "dark, windy and noisy" and that its conversion to commercial space would provide "retail continuity" with the remainder of Madison Avenue. On Feb. 27, 2010, ice fell through the glass ceiling of the atrium injuring s number of people attending a Purim party.
By 1996, Sony had consolidated most of the operations for its Sony Music Entertainment division at 550 Madison Avenue, for which The New York Times noted that "such high-profile and elaborate space is appropriate and necessary." That same year, Sony acquired additional space across the street at 555 Madison Avenue, a 445,000 square feet (41,300 m2) building built in the 1960s that underwent renovations of its lobby, windows, bathrooms and other common spaces in conjunction with Sony's lease. Sony signed leases through 2013 on an additional 90,000 square feet (8,400 m2) on the sixth through ninth floors of the building, on top of an initial rental of 90,000 square feet (8,400 m2) of space on the second through fifth floors of the building that it had made in 1995. Rents on the floors had averaged about $34 per square foot at the time. Sony connected the two buildings using fiber optic cables that were run under Madison Avenue and installed microwave communications equipment on the top of the 555 building. Sony made these moves, which included early termination of leases on space in the surrounding area at 711 Fifth Avenue on the 43rd floor at 9 West 57th Street, as part of an effort to lower occupancy costs by bringing its businesses closer together.
A cash-strapped AT&T sold the building to Sony in 2002 for $236 million, or $315 per square foot.
On February 27, 2010, the glass ceiling of the atrium of the building broke, injuring at lease 15 inside who were at a Purim celebration. The ice that accumulated from the Third North American blizzard of 2010 fell from an upper floor. Among those in the atrium was Snooki who was not injured and texted to her Twitter account "Omg roof just collapsed at the purim event!"
The Sony Wonder Technology Lab is a multimedia, hands-on tour through the world of media, located in a four-story annex accessible through a glass-roofed atrium that connects 55th and 56th Streets in mid-block.  Open Tuesday through Saturday, Sony bills the free exhibits as a "technology and entertainment museum for all ages". As of 2008, the museum's third and fourth floors were undergoing renovations expected to be completed in fall 2008. Until the project is complete, the music, film and video game exhibits on the building's second floor are open. Sony Wonder replaced Infoquest Center, a permanent telecommunications exhibition that had been built by AT&T. On February 28, 2010 ice broke through a glass atrium at the Sony Building. Ten people sustained minor injuries.