"Most people today think about little blue boxes or Audrey Hepburn in a tiara when they think about Tiffany & Co. However, way before it made jewelry, the company was known around the globe for its elegant decorative glass. One of the most spectacular displays of this craftsmanship is the world’s largest Tiffany glass dome in Chicago," The Culture Trip says.

"Fabricated in bright colors and arranged into dramatic windows and lighting, Tiffany’s glass work has often been described as paintings made out of glass. Chicago’s Tiffany glass dome is unquestionably one of the most spectacular ceilings in the Windy City—and perhaps the world.

"At 38 feet (11.58 meters) in diameter and 1,000 square feet (92.9 square meters) total, the colorful dome is a prominent feature of Preston Bradley Hall in the city’s Cultural Center downtown. Jacob A. Holzer, the leading mosaicist at Tiffany Glass and Decorating Company of New York in the late 1800s, designed the ceiling using roughly 30,000 individual pieces of glass. Each piece is shaped like a fish scale."

"The magnificent translucent dome, 38 feet in diameter and made of Tiffany Favrile glass, is cut in the shape of fish scales. At the top of the dome are the signs of the zodiac. At the base of the dome is a quotation from the British author Joseph Addison. The dome glass, lighting fixtures, wall sconces and chandeliers were made by the Tiffany Glass and Decorating Company of New York. The supporting frame was constructed by the Chicago Ornamental Iron Company," the City of Chicago says..

"Approximately 38 feet in diameter, the Tiffany dome spans more than 1,000 square feet. It contains some 30,000 pieces of glass in 243 sections held within an ornate cast iron frame. In order to restore the glass, the panels were removed from the framework and taken to a world-renowned glass studio. The panels were disassembled so that each piece of glass could be cleaned by hand and repaired as necessary, then reassembled with new leading.

"This project restored the dome to Tiffany’s original vision. Now the dome can be seen as it was in 1897, when the building opened as the first Chicago Public Library, and the room now named Preston Bradley Hall was where people picked up the books they had requested. The concrete and copper exterior dome that had been added over the art glass dome during the 1930s was removed. Natural light shines through the glass, changing the subtle colors of the restored glass minute–by–minute."

"The center’s Preston Bradley Hall is home to a 200-foot-diameter dome that is touted as the largest of its kind in the world—and with 1,134 square feet of colorful mosaics, including 30,000 individual panes of glass, the boast seems valid," the Atlas Obscura says.

"Completed in 1897, the dome was designed for the Chicago Public Library by Tiffany’s legendary “chief mosaicist” J. A. Holzer. When the Chicago Cultural Center acquired the gorgeously ornate building 1986, the center also inherited the masterpiece that graced the ceiling of the structure. Though the building was estimated to be worth $2,000,000, the dome alone is currently valued at around $35,000,000.

"Originally sunlit, the translucent dome portrays the 12 signs of the zodiac among fish scale-shaped pieces of glass embedded in ornate iron framing. In the 1930s, a protective outer dome was constructed, and while the new backlit appearance was lovely, many felt the dome lost much of its natural beauty."

"In 1894 in Queens, New York, Louis Comfort Tiffany first produced a type of iridescent art glass known as Favrile glass. Tiffany is possibly best known as the son of Charles Lewis Tiffany — the founder of Tiffany & Co. jewelry. Louis primarily used his Favrile glass in stained-glass windows. His style is different from others because the color is ingrained in the glass. The largest display of this glass can be found in the state of Illinois, at the Chicago Cultural Center," the Only In Your State says.

"A Chicago landmark operated by the city's Department of Cultural Affairs and Special Events, the Chicago Cultural Center opened in 1897. It is now considered to be one of the most comprehensive arts showcases in the country thanks to live theater, films, dance, lectures, family events, and more.

"The translucent dome is made of Tiffany Favrile glass, cut in the shape of fish scales. The entire dome measures 38 feet in diameter, spanning over 1,000 total square feet."

"The Chicago Cultural Center, opened in 1897, is a Chicago Landmark building operated by Chicago's Department of Cultural Affairs and Special Events. The Cultural Center houses the city's official reception venue, where the Mayor of Chicago has welcomed presidents, royalty, diplomats, and community leaders. It is located in the Loop, across Michigan Avenue from Millennium Park.

"The Chicago Cultural Center underwent an extensive renovation during 2021–2022 with the goal of unearthing the original beauty of the building. The meticulous restoration of the art glass dome and decorative finishes in the Grand Army of the Republic rooms, a Civil War memorial, was made possible by a grant of services valued at over $15 million to the City of Chicago. The Chicago Cultural Center is home to two magnificent stained-glass domes.

"The scope of the project included recreating long-lost light fixtures, cleaning and polishing old marble, restoring mahogany doors, installation of new glass, and restoration teams performed many meticulous hours removing layers of paint in the historic rooms. Also included in the scope was the complete restoration of the 40 ft (12 m) diameter Tiffany-designed stained glass dome, which had become covered in grime and paint. The dome contained over 60,000 individual pieces of glass to be restored. Daprato Rigali Studios of Chicago performed the stained-glass dome restoration." (Wikipedia)