The Chinese firm that can build a skyscraper in a matter of weeks

CNN)At the beginning of February, construction workers gathered at a sparse building site in the city of Changsha, south-central China.

A little under three weeks later, a 57-story skyscraper stood on the very same the spot.

The "Mini Sky City" tower is the work of Broad Sustainable Building, a Chinese firm that specializes in prefabricated construction.

By preparing more than 2,700 modules in a factory for four months before site work began, BSB says it was able to assemble the structure at the rate of three stories per day -- like a giant vertical jigsaw pieced together from a minutely detailed set of instructions.

A timelapse video of construction went viral on Chinese websites before finding its way onto many western news sites and broadcast media at the beginning of May.