The official religion of Japan is Shinto, and a simplistic description is that this is an old heathen region that has survived to modern times. A special trait in Shinto is the idea that the emperor is a descendant of the sun goddess Amaretsu. The entrance to a Shinto shrine is mark by a torii, an arc that always has this distinct form. Often it is in wood and painted brightly orange (which appears to bleach into pink by time), but you also see simpler torii in unpainted concrete. This torii, in size extra large, marks the entrance to Heian-jingu, the most important Shinto shrine in Kyoto.