Horyuji Temple is known for having the world's oldest wooden structures, and it became Japan's first UNESCO World Heritage Site in 1993.
Horyuji Temple’s wooden buildings, which have been in existence since the 7th century, undergo major maintenance and repairs every few hundred years. The Japanese cypress wood used in the buildings' construction fits precisely and warps little, making it well-suited to Japan's climate. When the structures are repaired, only the damaged parts are removed, and the major components are kept in use as they are. The buildings have been preserved this way for a millennium plus several hundred years.
Hokiji Temple is registered along with Horyuji Temple as a UNESCO World Heritage Site. Its Three-Story Pagoda standing in a pastoral setting is one of the best-known scenes in Ikaruga. Its horizontal dimensions roughly match those of the first, third and fifth stories of Horyuji Temple's Five-Story Pagoda. Reportedly built in 706, it is said to be the oldest existing three-story pagoda in Japan.