In the closing decades of the 19th century, New York underwent a profound physical and cultural transformation. Fueled by the wealth of the exploding financial and manufacturing sectors, the city rapidly evolved into a world-class metropolis. The bold ambitions of civic and business leaders, architects, and engineers of the era manifested in landmarks such as the vast Cathedral of St. John the Divine, the stately U.S. Custom House, the towering Municipal Building, and the original terminus of New York City’s first official subway line—the ornate City Hall stop. The sweeping interior spaces common to all of these structures, and hundreds of others, depended upon a venerable Mediterranean building technology adapted to contemporary American construction: arched tile ceilings—or vaults—that were not only self-supporting but could also bear the weight of floors or roofs above them. These vaults were designed and built by a single New York firm, founded by Spanish immigrant Rafael Guastavino (1842-1908) and later headed by his son Rafael Jr. (1872-1950). The Guastavinos’ patented system for building domes and vaults involved multiple layers of thin ceramic tiles bonded with quick-drying mortar. The resulting structures were not only exceptionally strong, but also lightweight, easy to build, and inherently beautiful, thanks to intricate patterns of exposed tile that formed finished, decorative surfaces. Guastavino vaults figured prominently in more than 1,000 projects across the nation, including 200 in Manhattan alone. During its 73-year history, the Guastavino Company helped build some of the most impressive interior spaces in America—veritable palaces for the people. This list based on MCNY's exhibition Palaces for the People, contains many of Guastavino's masterpieces in the five boroughs, both those that remain and those that have been lost to the wrecking ball.

Public School 183, 1920. A C.B.J. Snyder school was constructed in 1902 and opened in 1903. The school has a long history of promoting science-based learning and has been nicknamed the "School of Discovery." Today the school remains P.S. 183 and is named after Robert Louis Stevenson, the Scottish novelist and travel writer.

Originally founded in 1895 by Slovakian immigrants on the Lower East Side, the Church of St. John Nepomucene moved north to East 57th Street, before finally settling in Yorkville at First Avenue and 66th Street. Their current building, seen here in 1927 two years after it was completed, was designed in a Romanesque Revival Style by architect John van Pelt. The prominent tower, rose window, and brick and stone facade with intricate details stand out along the busy avenue to this day.