In 1900, New York architects Heins & LaFarge hired Guastavino to help construct City Hall station, the underground showpiece for the IRT, the first part of the then-new New York City Subway.
The station, although elegant, was never convenient or popular, as it was superseded by nearby stops with connections to Brooklyn.
After the city closed it in 1945 because needed upgrades were too expensive, it became a legendary abandoned Manhattan underground relic.
Subway buffs and urban spelunkers knew about it.
Guastavino also installed the ceiling of the south arcade of the Manhattan Municipal Building, which was constructed during 1907-1914.

The Guastavinos had entered New York as immigrants via Ellis Island.
In 1917 the younger Rafael Guastavino III was commissioned to rebuild the ceiling of the Ellis Island Great Hall.
The Guastavinos set 28,832 tiles into a self-supporting interlocking 56-foot (17 m)-high ceiling grid so durable and strong that during the restoration project of the 1980s, as many sources repeat, only seventeen of those tiles needed replacing.

The largest dome created by the Guastavino Company was over the central crossing for the Cathedral of St. John the Divine in Manhattan: it is 100 ft (30 m) in diameter and 160 feet (49 m) high.
This dome was intended to be a temporary structure, to be replaced by a high central tower.
In 2009 this "temporary" fix celebrated the 100th anniversary of its construction.
Guastavino received this contract due to the much lower price he could quote because his system served as its own scaffolding.
This was an extreme test of his system, however.
The masons had to work from above, each day adding a few rows of tiles, and standing on the previous day's work to make progress.
At the edges, many layers of tile were laid, and the dome thins as it rises toward the center.
In 1900, New York architects Heins & LaFarge hired Guastavino to help construct City Hall station, the underground showpiece for the IRT, the first part of the then-new New York City Subway. The station, although elegant, was never convenient or popular, as it was superseded by nearby stops with connections to Brooklyn. After the city closed it in 1945 because needed upgrades were too expensive, it became a legendary abandoned Manhattan underground relic. Subway buffs and urban spelunkers knew about it. Guastavino also installed the ceiling of the south arcade of the Manhattan Municipal Building, which was constructed during 1907-1914.
The Guastavinos had entered New York as immigrants via Ellis Island. In 1917 the younger Rafael Guastavino III was commissioned to rebuild the ceiling of the Ellis Island Great Hall. The Guastavinos set 28,832 tiles into a self-supporting interlocking 56-foot (17 m)-high ceiling grid so durable and strong that during the restoration project of the 1980s, as many sources repeat, only seventeen of those tiles needed replacing.
The largest dome created by the Guastavino Company was over the central crossing for the Cathedral of St. John the Divine in Manhattan: it is 100 ft (30 m) in diameter and 160 feet (49 m) high. This dome was intended to be a temporary structure, to be replaced by a high central tower. In 2009 this "temporary" fix celebrated the 100th anniversary of its construction. Guastavino received this contract due to the much lower price he could quote because his system served as its own scaffolding. This was an extreme test of his system, however. The masons had to work from above, each day adding a few rows of tiles, and standing on the previous day's work to make progress. At the edges, many layers of tile were laid, and the dome thins as it rises toward the center.
Rafael Guastavino