Gyeongju, North Gyeongsang Province
Students at the site of Hwangryongsa, or Hwangnyongsa, a former Buddhist temple, completed in the 7th century. It was an enormous 9-story structure, built entirely of wood with no iron nails. It had a standing total height of 80 metres, the tallest wooden structure in the world at the time. The pagoda stood until it was burned down during the Mongolian invasions in 1238.