Mather Tower

Mather Tower, later known as Lincoln Tower and now primarily recognized by its address, stands as a striking Neo-Gothic high-rise structure in Chicago, Illinois, USA. Situated at 75 East Wacker Drive in the downtown "loop" district, this 521-foot (159-meter) skyscraper has earned the moniker "The Inverted Spyglass" among Chicagoans due to its distinctive architecture. It features an 18-story octagonal tower atop a more conventional 24-story rectangular base. When completed in 1928, it briefly claimed the title of Chicago's tallest building and remains the city's most slender high-rise, measuring just 100 by 65 feet (30 by 20 meters) at its base. The upper octagonal spire's interior offers the least square footage per floor of any skyscraper in Chicago.

Designed by Herbert Hugh Riddle, the architect of the Chicago Theological Seminary, Mather Tower served as the headquarters for the Mather Stock Car Company, a firm specializing in rail cars for livestock transportation. Its design was strongly influenced by the innovative Chicago Zoning Ordinance of 1923, which imposed no height restrictions on new buildings as long as the top floor occupied no more than 25% of its footprint. This regulation led to a proliferation of tall and slender "setback" towers, with Mather Tower being an exceptional and distinctive example. The octagonal spire's top floor encompasses a mere 280 square feet (26 square meters) of floor space.

Alonzo Mather, the founder of Mather Company and a descendant of Cotton Mather, is credited with several distinctive design elements, including the octagonal tower. Initial plans called for constructing a second identical building on North Michigan Avenue, connected to the Mather Tower by a ground-floor arcade, but the onset of the Great Depression in 1929 led to the project's cancellation.

By the 1990s, Mather Tower had fallen into disrepair, and in 2000, the 4-story "cupola" atop the building was demolished due to structural deterioration and safety concerns. Damage was so extensive that consideration was given to dismantling the remaining 17 stories of the octagonal spire. However, in 2000, the Masterworks Development Corporation acquired the building and embarked on a comprehensive restoration project. In November 2002, a helicopter lifted the steel framework for a new cupola from a river barge to the tower's top.

Today, the lower rectangular section of the building houses the River Hotel, while the octagonal upper stories are occupied by a branch of the Club Quarters chain, providing corporate accommodations. Mather Tower received recognition as a Chicago Historic Landmark in 2001 and was honored with a National Preservation Honor Award from the National Trust for Historic Preservation in 2006.

The architecture of Mather Tower represents a Neo-Gothic style that was popular during the revival period of American architecture. This style, also known as the Gothic Revival, had a significant influence on American architecture following its origins in 18th-century England. Neo-Gothic elements are evident in many late 19th-century and early 20th-century buildings in Chicago and across the United States.

The building's exterior is clad in terra cotta, a material that gained popularity due to its durability and unique characteristics. Terra cotta has been used for thousands of years and was known for its strength and weather resistance. It is made from hardened clay and contains no harmful chemicals, making it desirable for construction. In the rapidly growing city of Chicago, as in other cities of the early 20th century, terra cotta's ability to absorb sound waves made it a practical choice to address urban noise pollution. Additionally, as buildings grew taller, the shift from heavy masonry walls to lightweight structures became necessary, and terra cotta cladding emerged as a lightweight and recyclable solution.

Interestingly, the deterioration of Mather Tower prior to its restoration in the early 2000s was not primarily due to the falling terra cotta cladding itself. Although terra cotta is durable, its design properties were not fully understood in the early 20th century, especially in terms of thermocycling and compressive forces, which can lead to deterioration. Unlike earlier designs that relied on the mass of masonry to absorb moisture, the transition to steel structures required new considerations. It is likely that the falling cladding resulted from cracking terra cotta caused by the high strain exerted by the building's structure.