National Youth Day is observed in Thailand every September 20, commemorating the birthdays of two significant monarchs: King Chulalongkorn and King Ananda Mahidol. Chulalongkorn, also known as Rama V, was born on this date in 1853 and is celebrated for his extensive social and governmental reforms that helped protect the kingdom from colonization. Ananda Mahidol, the eighth king, was born on September 20, 1925, and became king at the young age of nine. His reign was cut short when he was found dead six months after returning to Thailand in 1945. The celebration of National Youth Day aims to encourage young people to recognize their responsibilities toward national development, contributing to the stability and prosperity of Thailand.