Since Kannon is the most popular deity, there are many Kannon pilgrimage in Japan. Many people have made a Kannon pilgrimage since a long time ago. In the Kannon pilgrimage, you visit 33 temples which enshrine Kannon and collect sacred vermilion seals.
The Saigoku 33 Kannon pilgrimage is the most recommended one because all temples are worth visiting and are ready to accept pilgrims very well. As the name "Saigoku" suggests, the temples of the Saigoku 33 Kannon pilgrimage are located in the Kansai region. The Kansai region was the center of Japan before the Meiji period. Therefore, traditional Japanese culture remains. While you are making the Saigoku 33 Kannon pilgrimage, you naturally come in touch with Japanese culture.
It is important to write the reason why you collect sacred vermilion seals. In 718, Saint Tokudo met Enma who is the deity of hell and judges whether people go to heaven or hell in the Buddhism. Enma said to Tokudo, "I have to send too many people to hell. To decrease the number, I request you to inaugurate a Kannon pilgrimage. Here are 33 sacred seals. I will give you them." After Tokudo returned this world with the seals, he inaugurated the Saigoku 33 Kannon pilgrimage. That is, the 33 sacred seals will make you go to heaven.
In 2018, 1300 years will have passed since Tokudo received the 33 sacred seals. To commemorate this, the 33 temples of the Saigoku 33 Kannon pilgrimage have special events from 2016 until 2020. Therefore, it is a good chance to start making the Saigoku 33 Kannon pilgrimage.