Currently, 14 of the 15 largest prize pools in history have been WSOP Main Events. The second largest prize pool outside of the Main Event is the 2012 WSOP event known as The Big One for One Drop, held from July 1–3. It featured a buy-in of US$1 million, the largest in poker history. Of the buy-in, $111,111 was a charitable donation to the One Drop Foundation, and the WSOP took no rake. All 48 seats available for that event were filled, resulting in a prize pool of $42,666,672, with over 5 million dollars donated. The second largest pool for any event outside of the WSOP was the 2012 Macau High Stakes Challenge, with a HK$2 million (US$260,000) buy-in plus a rebuy option. The event drew a field of 73, of which 21 made a rebuy, resulting in a prize pool of HK$182,360,000 (slightly over US$23.5 million).