Today we celebrate Nag Panchami, a traditional worship of snakes and serpents. The worship is always offered on the fifth day of bright half of Lunar month of Shravan(July/August), according to the Hindu Calender.
The snakes blessings are sought for the welfare of the family.
A bath of milk is given to the snakes in order to worship them.
Image source: Naag poojaCC BY-SA 3.0