As night settles over the mountains and hills, the Tenno River is illuminated by the hundreds of lanterns decorating the boats of the Tenno Festival. Historically held on the fourteenth and fifteenth days of the sixth month on the lunar calendar, the sailing of the illuminated boats was a highlight of the celebration. Each year, temporary teahouses sprung up on the riverbank to cater to the crowds drawn by the festival. Today, the Tenno Festival is designated as a National Important Intangible Folk Cultural Asset and held in July. The former Owari Province composes the western half of modern Aichi Prefecture, including the city of Nagoya.