Tallest building (not structure, pyramid, etc.):
The Empire State Building, in New York City, New York, held the title of world's tallest building for the longest time (42 years), from 1931 (its completion) until 1973. It is 1,454 feet tall at the tip of its lightning rod on top of its broadcast antenna.
In 1973,the Sears Tower(renamed Willis Tower)was completed, and was 1,730 feet tall at the tip of its broadcast antenna. It became the tallest building in the world at this time through 1998.