Simplify the following text for a Grade 12 native English-speaking person.
Original: Euronext was formed on 22 September 2000 following a merger of the Amsterdam Stock Exchange , Brussels Stock Exchange , and Paris Bourse , in order to take advantage of the harmonisation of the European Union financial markets .
Simplified: Euronext was created on September 22 2000 , when the stock exchanges of Amsterdam , Brussels Stock Exchange and Paris Bourse were joined together in a merger .