The Bitcoin halving event is a pre-programmed event that occurs approximately every four years or after every 210,000 blocks are mined. During this event, the reward that Bitcoin miners receive for verifying transactions on the network is halved. This results in a reduction in the rate at which new Bitcoins are created, ultimately impacting the supply side of the cryptocurrency. The purpose of the halving event is to control inflation and ensure that the total supply of Bitcoin remains capped at 21 million coins.