According to the Brahma Purana, Lord Vishnu wanted a change from Vaikuntha, so he inquired from Narada Muni about a place on earth for diversion and sport. Narada suggested Sesachalam (the head of Ananta Sesa on this Earth).
“akhila bhuvana janma sthema bhangAdi leele
vinata vividha bhuta vrAta rakshaika dikshe |
Sruti Sirasi vidIpte brahmaNi SrInivAse
bhavatu mama parasmin Semushi bhakti rUpA ||”
Translation: May my mind & intellect meditate the form of Bhakti in Srinivasa, the highest Reality, revealed in the Vedanta as the Lord who creates, protects and destroys the whole universe with sportive ease and who has taken a vow to protects all creatures who seek him.