Yatra or Pilgrimage is an integral part of Hindu religious life. After you have fulfilled your duties as a householder, you turn your attention towards a spiritual life, and go on a pilgrimage to holy places. The Rath Yatra is actually the pilgrimage in reverse - instead of believers seeking out the deity inside a temple sanctum, here the deity appears on the streets, to mingle with the people.
The biggest Rath Yatra is in Puri on the east coast, at the beautiful Jagannath Temple. Idols of Lord Krishna, his brother Balarama (Balabhadra) and sister Subadhra are taken through the streets in a grand procession of three chariots. The chariots at Puri are huge and colourful, and it takes several people to pull them. Once set in motion, the chariots trundle on almost with a life of their own and cannot be stopped even if someone falls accidentally in the path (that's where the English word juggernaut comes from). The chariots come to a stop two miles away, at the Gundicha temple. After a week's stay at Gundicha, the deities then return to Jagannath Temple.
Beyond the colour and drama, the Rath Yatra also has a philosophical meaning. The Kathopanishad says:
Atmanam rathinam viddhi sareeram rathamevatu
Buddhim tu saarathim viddhi marah pragrahameva cha.
The Body is the Chariot and the Soul the Deity within.
Wisdom is the Charioteer, directing the Mind onwards.
(Photos courtesy Robert Taylor - thank you!)