Macau Special Administrative Region Establishment Day is celebrated every year on December 20.
This day was established to mark the universality of transition of Macau from the colony of Portugal to a special administrative division of the People's Republic of China.
Macau was administered by Portugal since the 16th century.
The region saw a major development and fast economic growth after arrival of the Portuguese colonizers.
The Portuguese administration started to weaken after World War II, when the population of Macau was dissatisfied with the Portuguese government.
After the overthrow of the Portuguese dictatorship in 1974 the new government of Portugal determined it would relinquish all overseas possessions, thus the long transition period of Macau from the possession of Portugal to China started.
The Chinese and Portuguese representatives signed a Sino-Portuguese Joint Declaration in 1987, making Macau a special administrative division of China.
The declaration came into effect on December 20, 1999.