The Bitcoin Halving is an recurring event in which the reward provided for mined blocks is halved. It is a deflationary mechanism to reduce the circulating supply of a cryptocurrency and to increase shortage.
For example, the reward for validated Bitcoin transactions is halved every 210,000 blocks and was initially 50 Bitcoin (BTC).
The first Halving took place on November 28, 2012. The block rewards were reduced to 25 BTC. The second took place on July 9, 2016 and the block rewards were reduced to 12.5 BTC. The third Bitcoin Halving on May 11, 2020. The current Bitcoin block reward is 6.25 BTC.
The next Halving will take place at block 840,000 and the block rewards will be slashed to 3.125 BTC. It is estimated that the next halving will take place in 2024.