Nagoya airport in Japan runs the Samurai Ninja Project to introduce the history of Central Japan to tourists.
The airport’s staff dressed up as ninjas for Ninja Day which is the 22nd day of the 2nd month because the Japanese word for two is ni (transliterated, natch) and ni ni ni is like Ninja. So it’s sort of like how May 4th is Star Wars Day because ‘May the Fourth be with you’.