Before they were starchitects, many designers were child prodigies. Take Daniel Libeskind, an accordion virtuoso at the tender age of 7, or Zaha Hadid, who designed her own childhood bedroom. If this sort of talent is a harbinger of things to come, then big things are in store for 9-year-old Lee Changsub.

The Seoul-based third grader has a remarkable fixation with skyscrapers. He has filled his head with engineering facts and his notebooks with intricate drawings of some of the world’s most-recognized supertalls, including One World Trade, Taipei 101, and the Burj Khalifa—floor plans, elevations, and height calculations included. Changsub’s drawings and remarkable knack for building stats has even landed him on Korean television.

In Seoul, one of Changsub’s favorite pastimes was watching KPF’s 123-story Lotte World Tower rise outside his window with binoculars. His parents reached out to KPF and the client, Lotte Group, to share their son’s fascination with their tower. Lotte and KPF decided to give him a hardhat tour of the tower. Earlier this month, KPF invited Changsub and his family to New York to tour the architecture firm’s offices (where KPF president James von Klemperer explained the intricacies of a tuned mass damper) and to tour its Hudson Yards projects.

Scroll through the slideshow to see Changsub’s drawings and photos from his tour at KPF.