Hundreds of Buddhist monks gathered together in Thailand on Monday, in honor of one of the most important Buddhist festivals of the year: Makha Bucha.

Alternatively known as Magha Puja or Sangha Day, the holiday occurs on the full moon of the third lunar month. The Sangha is a community of Buddhist practitioners. Some believe the word refers just to monks and nuns, while others believe all Buddhists are part of the Sangha.

The holiday is important since it honors the day that the Nepali spiritual leader Siddhartha Gautama, who became known as the Buddha, gave his first sermon to 1,250 monks who had spontaneously gathered to hear him. The sermon established the rules of monastic life.

In Thailand, Makha Bucha is marked with a massive lamp lighting ceremony at the Wat Phra Dhammakaya Temple, the world's largest Buddhist temple, located in a province north of Bangkok. Participants form long, straight rows around the golden dome of the temple and participate in meditations. The goals of the day are to purify the mind, to make a renewed commitment to Buddha's teachings and to pledge to do only good in the world.

Scroll down to see images of this fascinating ceremony in Thailand.

Guillaume Payen via Getty Images Buddhist monks hold lanterns during a yearly ceremony at Wat Phra Dhammakaya Temple in Thailand.

Guillaume Payen via Getty Images

Anadolu Agency via Getty Images Young monks in training are also part of the ceremony.

Anadolu Agency via Getty Images A closer view of the Wat Phra Dhammakaya Temple.

NICOLAS ASFOURI via Getty Images Hundreds of devotees gathered to meditate during the festival.

Anadolu Agency via Getty Images

Guillaume Payen via Getty Images

NICOLAS ASFOURI via Getty Images Buddhist monks hold candles during a lighting ceremony at Wat Phra Dhammakaya Temple.

NICOLAS ASFOURI via Getty Images As night falls, hundreds of candles light up around the temple.

Guillaume Payen via Getty Images The festival occurs on the full moon of the third lunar month.

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