Thermae Romae

Terumae romae is a movie starring Hiroshi Abe, Aya Ueto, and Kazuki Kitamura. Lucius, a Roman architect, is transported through time to modern-day Japan, where he learns about Japanese bathhouses and uses this to his gain back home.
The story follows a Roman architect named Lucius, who is having trouble coming up with ideas. One day, he discovers a hidden tunnel underneath a spa that leads him to a modern Japanese bath house. Inspired by the innovations found there, he creates his own spa, Roma Thermae, bringing in the modern ideas to his time.