Complex sentence: Completed in 1952, it was the first curtain wall skyscraper in New York City, although not the first in the United States Boley Clothing Company Building, Kansas City, Missouri (1909), designed by the Canadian architect Louis Curtiss.
Split into simpler sentences: Completed in 1952, it was the first curtain wall skyscraper in New York City, although not the first in the United States. The first in the U.S. was Boley Clothing Company Building, Kansas City, Missouri (1909), designed by the Canadian architect Louis Curtiss.