Rathayatra is the most extraordinary cart festival that originates in Jagannatha Puri on the east coast of India and dates back over 2,000 years. The Skanda Purana states that 'Ratha-yatra' began a few billion years ago in Satya-yuga during the reign of Svarocisa Manu, the second of the fourteen Manus.
In the United Kingdom there are Rathayatra festivals all over the country. They run from May through until October. The largest is London which was one of the first outside India in the 60s and has been running ever since. There are big Rathayatras in Birmingham, Leicester, Brighton and Cardiff. Dublin and Belfast also hold Rathayatra.
In 2016 the International Society for Krishna Consciousness will hold over 500 Rathayatra festivals around the world.
Rathayatra (ratha yatra) has several meanings. The literal translation from sanskrit is 'cart festival'. But of course there is much more to it.
His Divine Grace A.C. Bhaktivedanta Swami Prabhupada described the meaning of Rathayatra on several occasions.
"Just try to understand Jagannatha. Jagat means the moving world, gacchati iti jagat. The Sanskrit word gacchati means that which is moving--all these planets, the universe, the sun--everything is moving, and we are moving. Jagat-natha, natha means master and proprietor. Therefore, Jagannatha means the proprietor or the master of all these movements. And Balabhadra, Balarama--bala means strength and rama means enjoyment. Balarama means He who gives you spiritual strength for enjoying eternal blissful life. Subhadra--su means auspicious and bhadra means well-being. Subhadra, Jagannatha and Balarama combined together are present here to reclaim you all from your miserable condition of life. That is the purport of this Ratha-yatra festival. If anyone sees Jagannatha, Subhadra and Baladeva on the cart, then he does not take birth again in this material world. Ratheja vamanam drsta." (7/5/70 San Fransisco Rathayatra)
"Jagannatha svami nayana-pathagami bhavatu me."
So if we want to have eternal life, full of knowledge and blissfulness, then we must take to Krsna consciousness. Our, this Krsna consciousness movement is the greatest welfare activities in the human society. We are giving information to every man, without any discrimination of cast, creed, or color, that every human being especially, not only human being, all living entities, including the animals, beasts, birds, trees, aquatics--everyone--they can achieve to the highest perfection of life by this Krsna consciousness. But especially the extra intelligence of the human being can be utilized to realize Krsna. If we don't do that, we are missing a great opportunity. So our request to everyone is to understand this philosophy of Krsna consciousness. I have already explained what is this Ratha-yatra festival. It is in commemoration of a grand visit by Lord Krsna along with His elder brother, Balarama, and His younger sister, Subhadra, in a solar eclipse ceremony at Kuruksetra. This occasion is the subject matter of this Ratha-yatra festival. Apart from these historical references in the matter of Ratha-yatra festival, there is another spiritual meaning, that the Lord is situated in everyone's heart, and this body is just like ratha, or car. He is sitting in everyone's heart. It is stated in the Bhagavad-gita, sarvasya caham hrdi sannivistah: "I am sitting in everyone's heart." Mattah smrtir jnanam apohanam ca. ([Bg. 15.15]" (27/6/71 San Francisco Rathayatra)
In a purport of Sri Caitanya-caritamrta, His Divine Grace Srila Prabhupada gives a wonderful illumination about the esoteric meaning of Lord Jagannatha's Ratha-yatra.
After giving up the company of the Vraja-gopis, Vrajendranandana performed His pastimes in Dvaraka. When Sri Krsna visited Kurukshetra during a solar eclipse, He was accompanied by Baladeva, Subhadra, and other Dvarakavasis. At Kurukshetra, Krsna again met the Vrajavasis, especially Srimati Radhika and His beloved sakhis.
Sri Ksetra, Jagannatha Puri, was taken as the kingdom of Dvaraka, the place where Sri Krsna enjoys supreme opulence. However, Krsna was being led by Mahaprabhu to Vrndavana (represented by Gundica Temple), the simple village where all Vrajavasis are filled with ecstatic love for Krsna. Sri Ksetra, Jagannatha Puri, is a place of richly opulent pastimes (aisvarya-lila) just as Vrndavana is the place of intimate conjugal pastimes (madhurya-lila).
Lord Gauranga's following at the rear of Lord Jagannatha's car indicated that Lord Jagannatha, Krsna, was forgetting the Vrajavasis. Although Sri Krsna neglected the Vrajavasis, He never forgot them. Thus in His opulent Ratha-yatra, Sri Krsna was returning to Vrndavana. In the role of Srimati Radhika, Sri Caitanyadeva was examining whether Sri Krsna still remembered the Vrajavasis. When Lord Gauranga fell behind the Ratha car, Jagannatha-deva, Krsna Himself, understood the mind of Srimati Radhika. Therefore, Jagannatha sometimes fell behind the dancing of Sri Caitanya Mahaprabhu to indicate to Srimati Radhika; He had not forgotten.
Thus Lord Jagannatha waited on His cart for their forward march. In this way, Lord Jagannatha showed that He could not feel satisfied without the ecstasy of Srimati Radhika. While Jagannatha thus waited, Gaurasundara, in His ecstasy of Radha, immediately rushed foward to Krsna. At such times Lord Jagannatha proceeded very slowly.
These competitive exchanges were all part of the love affairs between Sri Krsna and Srimati Radhika. In that competition between Mahaprabhu's ecstasy for Jagannatha and Jagannatha's ecstasy for Srimati Radhika, Mahaprabhu emerged successful. This is the purport of the Ratha-yatra cars going from the Jagannatha Temple to the Gundica Temple. (Cc. 2.13.119 p.)
Rathayatra was brought to the western world by His Divine Grace A.C. Bhaktivedanta Swami Prabhupada in 1967. In fact the Ratha Yatra festival has a long history going way back. "The Skanda Purana states that Ratha-yatra began a few billion years ago in Satya-yuga during the reign of Svarocisa Manu, the second of the fourteen Manus. Every year Lord Jagannatha enacts the Ratha-yatra (Mahavedi Yatra) in order to see His appearance place at the Yajna Vedi in the Gundica Mandira. (Skanda P. 29.25-44)
In Orissa (India), the Ratha-yatra festival is known as Jagannatha's journey to Gundica. Although outsiders call it Ratha-yatra, the residents of Orissa call it the Gundica-yatra in honor of Gundica Devi, King Indradyumna's queen, who purportedly initiated this festival. The songs of many Oriyan poets state that Ratha-yatra started with the request of King Indradyumna's wife named Gundica. Ratha-yatra is also known as the Patita Pavana Mahotsava because non-Hindus get the opportunity to see Lord Jagannatha. This auspicious darsana cleanses all sins and grants liberation."
('Jagannatha Puri Guide Book' by Mahanidhi Swami)
The history of Jagannatha worship dates back beyond any known records.
"Ancient scriptures state that Jagannatha worship has been going on eternally. The Rg Veda mentions it and the Puranas (Skanda, Brahma, Narada) present elaborate descriptions of Sri Ksetra Dhama. The Ramayana and Mahabharata refer to the Deity of Jagannatha Deva.
During the last two thousand years of continuous worship the cult of Jagannatha has assimilated the practices and philosophies of many religious faiths.
Consequently, the cult of Jagannatha worship symbolizes the unity in diversity of all the major religious cults of India, including tree and totem pole worship (the Sabara cult); Jainism; Buddhism; the cults of Purusottama, Vasudeva, Madhava, Rama and Laksmi Nrsimha; and Panca Upasana worship (five-fold Hinduism) as Vaisnavism (Visnu worship), Saivism (Siva worship), Saktism (Durga worship), Ganapatya cult (Ganesh worship) and Saurism (Suryadeva worship).
"Jagannatha represents an integration of all the important Hindu cultures that had flourished in India, including the Vedic, Puranic, Tantric, Smarta, Vaisnava, Jainism, Buddhism and the aboriginal tribes. Jagannatha is worshiped as Visnu or Narayana when He sits on the simhasana in the sanctum sanctorum; as Ganesa during Snana Yatra; as Rudra during the Nava Kalevara ceremony; as Durga in the Sayana festival and as the Sun when riding on the chariot during Ratha-yatra.
Apart from this, pilgrims worship Jagannatha according to their religious persuasion. Ramanuja Vaisnavas worship Jagannatha as Narayana, Nrsimha, Hari; Ramanandi Vaisnavas adore Him as Rama; Gaudiya Vaisnava worship Jagannatha as Krsna; and Oriyan Vaisnavas see Jagannatha as the combined form of Radha-Krsna. Hence, Lord Jagannatha represents an assimilation of all the religious cults, creeds and sectarian philosophies under the broadest sense of the term Hinduism." (Jagannatha Puri, temple pamphlet.
It appears that people worship Lord Jagannatha according to their own realization.
Sri Caitanya Mahaprabhu and His followers see and worship Sri Jagannatha Deva as identical with Bhagavan Sri Krsna, the original, Supreme Personality of Godhead.
The Gaudiya Vaisnava view is supported by the fact that Jagannatha Swami's pujaris use two krsna-mantras in their daily worship of Lord Jagannatha: gopijana vallabhaya svaha and klim krsnaya govindaya gopijana vallabhaya svaha.
Sri Baladevaji is worshiped as the son of Vasudeva with the mantra om namo bhagavate vasudevaya.
Subhadra is worshiped with the bija-mantra Hrim.
Incidentally, the Oriyan Vaisnavas pronounce Krsna as Krusna."
('Jagannatha Puri Guide Book' by Mahanidhi Swami)