Visakha Puja Day is an important day in Buddhism.  Visakha Puja Day marks the Buddhism Trinity or three important incidents occurred in the life of Lord Buddha on the same day. They happened on the same day on full moon of the sixth lunar month.

The three significant separate events are:

In his early years he lived a life of luxury and was shielded from the life of misery that most of the kingdom’s people lived in. At the age of 29 he left this life of luxury and studied the practices of Brahmin ascetics who denied themselves all but the most vital essentials of life. Eventually he rejected this practice and practice the "middle way" – a simple rational life of moderation. At the age of 39 he attained enlightenment. His discovery is referred to as the four noble truths:

He spent the remainder of his life wandering from place to place teaching his discoveries.

Visakha Puja day was first celebrated in Thailand during the Sukhothai period (12-13th century). Typical activities would include: Going to temple for special observances and listening to Dhamma teaching, giving food to the Monks, and Keeping the Five or Eight precepts.

One final note: In 1999 the United Nations unanimously resolved to declare Visakha Puja day an International day.