Saudi Arabia decided to stop using only the US dollar for selling oil, which was the rule for more than 50 years. Now they want to use other currencies like the Euro, Yen, and Yuan, as well as cryptocurrencies. They're doing this to rely less on the US dollar. Saudi Arabia is also part of a project led by China called Project mBridge, which is about using digital currencies between countries. This could make more countries use different currencies instead of just the US dollar. This change might make Bitcoin and other cryptocurrencies more popular because they are not controlled by any one country and there is only a limited amount of them. Some experts think that if the petrodollar deal ends, the US might print more dollars, which could make prices go up, so people might want to invest in Bitcoin instead. This change in the US-Saudi petrodollar agreement, which started in 1972, is a big deal. It means that more countries might start using different currencies for trading, which could affect the world's financial markets. The Bank for International Settlements (BIS) says that Saudi Arabia is actively taking part in Project mBridge and trying to work with more countries economically.