Simplify the following text for a Grade 7 native English-speaking person.
Original: The organization was founded on 8 December 1991 by the Republic of Belarus , the Russian Federation , and Ukraine , when the leaders of the three countries met in the Belovezhskaya Pushcha Natural Reserve , about 50 km ( 30 miles ) north of Brest in Belarus and signed a Creation Agreement ( , Soglasheniye ) on the dissolution of the Soviet Union and the creation of CIS as a successor entity to the USSR .
Simplified: On December 8 1991 , leaders of Russia , Belarus , and Ukraine met in a place in Belarus . They met in a Natural Reserve named Belovezhskaya Pushcha .