That Luang Festival is celebrated during the full moon on November every year.
This main religious festival is
only last 3 days and nights but the Trade Show selling textiles,
handicrafts, wooden carvings, clothing and industrial products from
locals and international countries last for a week.

Pha
That Luang monument is a sacred
site, because Lao's people believe the stupa enshrines a relic of
Buddha. Therefore, during this festival thousands of monks from all
over Laos come to Vientiane to celebrate this important festival. The
open ceremony always attended by government leaders, representatives of
state, private sectors, international organizations and people from all
parts of the country.
During the festival there is
procession of laypeople begins at Wat Si Muang in the city center to Pha
That Luang monument to make
offerings to the monks, by night people carrying incense and candles as
offerings, circumambulate That Luang monument three times in honor of
Buddha.
At night there are folk and
popular music troupes and drama performances provide entertainment at
the festival. Festival goers can have fun, buy goods and food at the
fair all night long. On the final day at dawn the public make offerings
of food and money to the monks.
The festival is an opportunity
to demonstrate the rich and diverse cultural identity of Laos, with
participation of every ethnic minority groups from around the country.
The celebration is also enable Lao people and foreigners to enjoy
learning about Lao traditions and culture.
This year thousands of people
gathered at That Luang temple in the early morning to give alms to the
hundreds of monks hoping for good luck, good health and prosperity for
the country. The 24 Miss Laos 2010 Finalist Contestants were also there
to take part in the ceremony.