From an English language pamphlet about Ise:

"Since ancient times, the Japanese people have lived in accordance with nature. All over Japan, there are consecrated rocks and evergreen trees in which kami (powerful beings) reside, as well as sanctuaries (generally called jinja) in which kami are enshrined and which usually consist of a building surrounded by a grove of trees. According to Shinto (literally, 'the way of kami'), the indigenous religion of Japan, kami are worshipped in matsuri which include solemn ceremonial occassions as well as festivals at the local level. There are more than 100,000 Shinto sanctuaries in Japan, which are at the center of spiritual life. Historically, Jingu has held the most honored place among all Shinto sanctuaries. It is considered to be the spiritual home of the Japanese people, most of whom wish to make a pilgrimage to Jingu at least once during their lifetime. In fact, more than six million pilgrims and worshippers come to Jingu every year."

(Jingu is the proper name of the two shrines at Ise that I visted today)