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.

Ansehe Chesed Synagogue ca. 1910 Jewish residents were a significant presence in post-Civil War Harlem, which at the turn of the twentieth century was the nation's pre-eminent middle class Jewish neighborhood. If, in their religious structures, Harlem's Jews avoided Christianity's distinctive Gothic mode, but they were not averse to presenting a "churchly" appearance. Temple Ansche Chesed was completed in 1909 on a fine corner site at Seventh Avenue and West 114th Street. The structure is built of brick, limestone, and terra cotta. It was lit naturally by means of an enormous skylight, the stained glass of which depicted traditional Jewish symbols. Congregation Ansche Chesed was a Reform congregation, with mixed seating for men and women and prayers conducted in English. It also boasted a fine organ. Since 1927, the congregation has worshipped in a similar building by Edward Shire located at 251 West 100th Street. Reflecting Harlem's history of changing demographics, Temple Ansche Chesed was adapted in 1926 as Our Lady of the Miraculous Medal, a Spanish Roman Catholic church, and then became Mount Neboh Baptist Church in 1980.

Ansche Chesed Synagogue, ca. 1910. The Congregation Ansche Chesed was established in 1828 by a group of German, Dutch and Polish Jews who split off from Congregation B'nai Jeshurun. The community was originally based on the Lower East Side and their first purpose-built synagogue was on Norfolk Street (now the Angel Orensanz Center). As the city expanded northward, the community moved in that direction as well. After calling a number of buildings home the congregation, now consisting of traditional German Jews and recent immigrants, settled in a new building in fashionable Harlem on 114th Street. The grand synagogue was fashioned as neo-Classical temple with a large portico and massive columns. Designed by Edward I. Shire, the cornerstone dates the building with dual dates, 1908 and 5668, on the Hebrew calendar. The building served the community well, but by the 1920s a larger space as needed. A new synagogue was constructed on the corner of 100th Street and West End Avenue. The community moved to that space in 1928. The building at 114th Street became the Roman Catholic Church of Our Lady of the Miraculous Medal (Iglesia de Nuestra Señora de la Milagrosa), which served the Hispanic community in Harlem. Since 1980, it has housed the Mount Neboh Baptist Church.