Tomorrow, 1 World Trade Center will become the tallest building in NYC.

The addition of a steel column will put it 21 feet taller than the Empire State Building.

This is the second time a skyscraper called 1 World Trade Center has edged over the Empire State Building. The first was on Oct. 19, 1970, when a section of steel framework elevated the north tower of the trade center to 1,254 feet, four feet above Empire State’s 1,250-foot benchmark.