As the tallest building in the world built by a human workforce (2,716.5 feet), it’s no wonder so many workers were engaged in the Burj Khalifa’s construction. It took over 100,000 tons of concrete and 55,000 tons of steel. To erect the 164-floor building (one of which is underground), thousands of people were hired. At the busiest period of construction, over 12,000 people were actively involved.