The Festival of the Chariots is sometimes referred to as Ratha Yatra, literally meaning Chariot Festival. Ratha Yatra originated 5,000 years ago in India, on the East Coast state of Orrisa, in a city called Jagannatha Puri.
The Festival celebrates Lord Krishna's return to Vrindaban and is held annually in the months of June-July to honor Lord Jagannatha, which means Lord of the Universe. Lord Jagannatha is a particular Deity form of Lord Krishna, fashioned from neem wood and brightly painted. The residents of Puri have been worshipping this form for many centuries. Five hundred years ago, Lord Chaitanya, the most merciful incarnation of Lord Krishna used to daily visit Lord Jagannatha in the temple and see Him in a mood of intense separation, much like Srimati Radharani who was parted from her beloved Krishna most of her days.
For the festivities; there are three chariots, one for each of the three deities; Lord Jagannatha, Lord Balarama and Lady Subhadra. The canopied chariots are decorated with flowers and balloons and are pulled with long, thick ropes by hundreds of people. The chariots are accompanied by a procession of devotees who are ecstatically dancing and chanting the Lord's Holy Names:
Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare Hare Rama, Hare Rama, Rama Rama, Hare Hare.
This Maha-Mantra or great chant is found in the Puranas and Upanishads and is specifically recommended in this age of Kali as the means of God realization. Lord Chaitanya personally designated it as the Maha-Mantra and practically demonstrated the effects of the chanting.