Passage: In the late 19th and early 20th centuries the corporate culture of New York was a primary center for the construction of skyscrapers, and was rivaled only by Chicago on the American continent. There were also residential sections, such as the Bowling Green section between Broadway and the Hudson River, and between Vesey Street and the Battery. The Bowling Green area was described as "Wall Street's back yard" with poor people, high infant mortality rates, and the "worst housing conditions in the city". As a result of the construction, looking at New York City from the east, one can see two distinct clumps of tall buildings—the financial district on the left, and the taller midtown district on the right. The geology of Manhattan is well-suited for tall buildings, with a solid mass of bedrock underneath Manhattan providing a firm foundation for tall buildings. Skyscrapers are expensive to build, but when there is a "short supply of land" in a "desirable location", then building upwards makes sound financial sense. A post office was built at 60 Wall Street in 1905. During the World War I years, occasionally there were fund-raising efforts for projects such as the National Guard.On September 16, 1920, close to the corner of Wall and Broad Street, the busiest corner of the financial district and across the offices of the Morgan Bank, a powerful bomb exploded. It killed 38 and seriously injured 143 people. The perpetrators were never identified or apprehended. The explosion did, however, help fuel the Red Scare that was underway at the time. A report from The New York Times:

Question: What type of buildings were mostly constructed during 19th and 20th centuries in New York?
skyscrapers