(CNN) — Every spring, thousands of monks gather at the ancient Borobudur Temple in Java, Indonesia, on the most important day on the Buddhist calendar: Buddha Day.
Also known as Waisak Day or Vesak Day, the holiday marks the birth of Gautama Buddha -- the father of Buddhism, who is responsible for the religion's core teachings.
Robe-clad monks circle the 9th-century temple -- the world's largest Buddhist temple and a UNESCO heritage site -- to meditate, chant sutras and release an ocean of glowing lanterns into the night sky.
It's just one of many celebrations taking place across Asia this month as worshippers ring in the holiday at the region's most beautiful temples, from lantern festivals at Seoul's Jogyesa Temple to rituals at Yangon's goldenShwedagon Pagoda.
Indonesia's Borobudur Temple.
Ulet Ifansasti/Getty Images AsiaPac/Getty Images
About Vesak Day
Born in Nepal in 567 BC, Gautama Buddha -- or Prince Siddhartha Gautama at birth -- was the son of a tribal leader.
As an adult, he founded a sect of wandering ascetics and the community eventually evolved into a religion after his death at 80 years old.
Today, over 488 million people -- or roughly 9% of the world's population -- practice Buddhism, nearly 99% of which are located in the Asia-Pacific region.
Each year, on the full moon of the month of Vesakha (usually falling in May or June in the western calendar), millions of Buddhists around the world take part in Vesak Day celebrations.
Not only does the date of Vesak Day change year after year, but it can also be different among cultures, depending which calendar they subscribe to.
In China and Hong Kong, for example, which follow the Chinese lunar calendar, worshippers observe Buddha Day on the eighth day of the fourth month (usually in early May).
So while Buddhists in Hong Kong marked Buddha Day on May 3 this year, Thailand celebrates on May 10.
The holiday goes by dozens of names -- but many countries unofficially refer to it as Buddha's Birthday or Buddha Day.
It celebrates three important events of Buddha's life: birth, enlightenment, and death -- said to have occurred on the same calendar day, albeit many years apart.
Celebrations around the world
From Thailand to South Korea, Myanmar, China and Malaysia -- every country has its own traditions, each symbolizing various aspects of Buddha's life or teachings.
Home to 255 million Buddhists -- the world's largest Buddhist population -- China sees one of the most widespread celebrations.
Most of the action revolves around Buddhist temples, where people light incense and leave offerings.
In South Korea, the holiday comes to life in a Lotus Lantern festival, best viewed at Seoul's Jogyesa Temple.
Temples are draped in thousands of colorful paper lanterns. It's also common for temples to offer bibimbap and tea to those who visit on the holiday.
Meanwhile, in Sri Lanka, people decorate their homes with paper lanterns. Colombo's Gangaramaya Buddhist Temple hosts a colorful Vesak Day festival.
In Ipoh, Malaysia, Buddhist devotees practice the ritual of "Sunning Buddha."
At Ipoh's Enlightened Heart Tibetan Buddhist temple, monks place a sacred Tibetan Buddhist painting -- called a "Thangka" -- in the sun to absorb its powers.
The energy is believed to promote peace, health, and harmony for the rest of the year.
And in Nepal, where Buddha was born? Thousands of Buddhists flock to Lumbini, his birthplace, where they donate supplies to disadvantaged communities and pay tribute to monasteries.
Explore Vesak Day around the world in the above gallery, which highlights past celebrations and ongoing preparations for this year's festivals.
Vesak is a religious and cultural festival in Sri Lanka. It is celebrated on the day of the full moon in the month of May.
Vesak Day is one of the biggest days of the year and is celebrated by Buddhists all over the world. Buddhists commemorate the important events that took place in the life of Lord Buddha on this day. First comes the birth of Siddhartha Gautama in Lumbini in Nepal which took place under the arbor of Sat trees where queen Mahamaya gave birth to him. The second event was Siddharta Gautam’s supreme attainment as the Buddha, the Enlightened One. The third event was Lord Buddha’s Parinibbana over 2500 years ago at Kusinagar.
Many temples get filled with devotees and pilgrims all over the country to mark this great event. In temples Buddhists worship, offer flowers, light lamps and burn incense. These traditional observances, in essence, have their value in satisfying the religious and emotional needs of the people.
Buddhists generally wear a white dress and go to the temple and participate in the traditional ceremonies.
Many of them spend the whole day in the temple and reaffirm their determination to follow the teachings of Buddha.
On this holy day the ‘Dana’ (alms giving) plays an important role. This is a sign of sharing joy and peace with people. During the Vesak Festival week, the selling of alcohol and flesh is usually prohibited, with abattoirs also being closed.
Other than the exclusive religious aspects of the festival, the Buddhists of Sri Lanka, decorate their houses and public places and arrange for various cultural events.
Birth of Siddharta Gautam
The Siddharth or lord Buddha, the divine creature inquired about five affairs before expiring for the final birth. The inquiries are the: right time, right area, right continent, right caste and right mother.
Then, as any Buddhists know, the fully mindful divine being entered the womb of Queen Mahamaya. A prince was born on a Vesak Poya day to the Queen and King Suddhodana and was named Siddhartha, one who has found meaning of existence. The Queen passed away seven days after the prince’s birth.
Attainment as Lord Buddha
Gautama Buddha was trained in various mental skills under many teachers, only to get disillusioned that they do not have the truth he looked for. The right way to achieve the truth dawned on him one day. He directed his mind in the path of meditation. Moments later he reached enlightenment and conquered the world of sorrows on Vesak Poya day.
Lord Buddha’s Parinibbana
80-year old Gotama Buddha then announced His passing away, Parinibbana, would take place on the third watch of the night at Sal grove of Malla royal family, and it happened to be a Vesak Poya day.
Vesak Pandols (Thorana) in Sri Lanka
In Vesak Season in electrically lit Vesak pandols called thoranas are erected island wide at public places, being mostly sponsored by donors, religious societies and welfare groups. Each pandol illustrates a story from the 550 ‘Jathaka Katha’ or the 550 Past Life Stories of the Buddha.
Vesak Lanterns in Sri Lanka
Vesak lanterns called Vesak koodu are lit in most of the homes in Sri Lanka on Vesak poya day. The lighting signifies an offering to the memory of the Buddha who delivered the message of Dhamma. In ancient times, people used their clay oil lamps for illumination. When candles became popular, colourful lanterns were made in different shapes and colours were used. Many associations arrange competitions on Vesak lanterns with the creators of the most beautiful lanterns being awarded valuable prizes.