An estimated 40,000 workers contributed to the construction and preparation of the Chicago 1893 World’s Columbian Exposition. Construction fell far behind due to labor strike, weather, and planning delays. And, to prepare the massive event for its opening ceremonies, organizers had approximately 20,000 at work in a last-ditch effort.

Construction tools, techniques, and technology have come a long way since then. We’re able to take on more complex projects more efficiently. To put things in perspective, about 10,000 workers contributed to construction of the recently completed 1 World Trade Center tower in New York City.