The temple of Guruvayur is situated in Thrissur District, Kerala, India. The temple is believed to be around 1000 years old. The place is also called 'Bhooloka Vaikundam' which means the abode of the Lord Vishnu on earth. The place is also called 'Dwaraka of the South'.
The deity of Guruvayur is believed to be 5000 years old. It has been worshiped by Lord Krishna himself at Dwaraka. At the time when Lord Krishna was about to leave this world - he gave this deity to Udhava. Udhhava was instructed to find a suitable place to install the deity. Lord Krishna told Udhhava that this deity would always be there to rescue the sufferers in this world. At that time, there was a huge flood and the whole city was immersed in water.
The deity was floating through the water when, Brihaspathi - Guru of Devas, and his disciple Vayu - God of Wind found the deity. Now they needed a place to install this deity. They went around the world to find a suitable place to install the deity of Lord Krishna. They reached a place, now Kerala where Lord Siva and Goddess Parvathy were present. Guru approached Lord Siva to get permission to install the deity. Lord Siva allowed the deity to be installed near a lake. The place thus got the name Guruvayur.
So at Guruvayur, Lord Krishna, still offers his blessings to all his devotees. There is a temple of Lord Siva at Mammiyoor and the pilgrimage to Guruvayurappan is considered complete only if you visit Mammiyoor.