Dating from 1707, Zenkoji is a designated National Treasure. Zenkoji is an important pilgrim's destination and remains an authentic centre of worship in Japan. One of my favourite things to do in Nagano in the evening is to take a walk through Zenkoji Temple. It is such a peaceful place.
There is a pitch black tunnel underneath the Main Hall where you can walk around. It is said that this is the temples "place for enlightenment" and that all people here are equal. There is a key to Paradise that you can feel for whilst in the tunnel. The idea is that you should free yourself of worldly thoughts and engage in self-reflection.
You can catch a 100 yen bus from Nagano Station or it is a pleasant walk through the shopping area up a small hill to the temple.
To enter the Main Hall (and tunnel) and to view an old prayer wheel and a museum underneath the main pagoda a fee of 500 yen is charged. A brochure in English will be provided. Entrance into the grounds of the temple is free.