Hm. The pyramids were an architectural and supply chain genius stroke considering when they were made. It also took fantastic human sacrifice to achieve that. One world trade center was built with the assistance of trains and semi trucks brining ore to smelters and steel to the construction site, electricity, cranes etc.

Minus the slavery, have we really expended that much human effort and equivalent wealth and time on something in the modern era? The only thing I can think of is Free software products, shit like Linux.