U.S. and worldwide economic crisis, 1973–1975
The 1972 construction of One World Trade Center, the 1973 completion of Two World Trade Center, and the 1974 construction of the Sears Tower in Chicago coincided with a period of speculation in monetary expansion from foreign lending.
It also coincided with the collapse of the Bretton Woods system, a rise in oil prices that caused a global economic crisis, and speculation in stocks, property, ships, and aircraft.
Source: Barclays