Halving day 2012
Halving day 2012 (November 28, 2012) was the day of the first subsidy halving, which occurred when block 210000 was solved. Until block 420000, the block reward would be 25 BTC instead of the original 50 BTC.
At the moment before the halving, 10,500,000 BTC had been mined, 50% of the target cap.
SolutionSlush's pool was responsible for finding the solution, and a miner named laughingbear contributed the solution.
The block was solved by a Radeon HD 5800 after mining for less than a week. This GPU would later be sold to Chaang Noi at a significant markup on August 26, 2013. Several images of the card were posted to Bitmit, but no copies are currently known to exist.