One Prudential Plaza (formerly known as the Prudential Building) is a 600-foot-tall, 41-story structure in Chicago completed in 1955 by the architectural firm Naess & Murphy, and constructed by the George A. Fuller Co. It is categorized as an International Style building, a response to move away from the ornate architecture of the 19th century. The general public did not warm up to the bland concrete slab style at first.
The building served as headquarters for Prudential's Mid-America company, and was the tallest structure in the city at the time. It was built on real estate air rights, the area above the Earth's surface, over the vast Illinois Central Railroad yard, eventually paving the way for today's Millennium Park to the south. Offset atop the building was a mast that served as a broadcasting antenna for Chicago's WGN-TV. The building was home to the Chicago Tribune and Tribune Publishing after leaving Tribune Tower in July 2018. The Tribune moved out of One Prudential Plaza and relocated its offices and newsroom to the Freedom Center at the beginning of 2021.
It was the city's first downtown skyscraper in twenty-one years and included a must-see observation deck. It was reported that 1.5 million people visited the deck in its first three years of existence. The building included two restaurants: Stouffer's Gibraltar Room, located off the lobby, and Stouffer's Top of the Rock on the 41st floor. The novelty of viewing four states on a clear day succumbed to taller buildings erected near it, making Lake Michigan the only distant view. The Top of the Rock closed in 1976, and the Gibraltar Room in 1982.
The original 200-foot Prudential signage was red and used a bold sans-serif font in capital letters. Very easy to read even from some distance. The replacement sign was a blue serif font, including a modernized Gibraltar logo. Being distanced from the building's surface, it cast a confusing drop shadow and is nearly impossible to read on sunny days. The blue signage will eventually be removed by the current owners, Wanxiang America Real Estate Group, for Prudential began moving out of the original building and its newer, 61-story skyscraper in 2024 to smaller confines directly west along the Chicago River. Not being removed (above) will be the Rock of Gibraltar, a 65-ton, 30-foot-high two-dimensional carving on the west side of the original building, designed by artist Alfonso Iannelli.
