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Yesterday was January 15th on the lunar calendar, so most Vietnamese went to Buddhist temples, and some houses and businesses gave out free food, as at this store here, with its huge pot of vegetarian rice gruel.

Technically, it's the Lantern Festival, but I only saw them at Buddhist temples.

Here is one explanation for the festival, according to Wikipedia:

Yet another common legend dealing with the origins of the Lantern Festival speaks of a beautiful crane that flew down to earth from heaven. After it landed on earth it was hunted and killed by some villagers. This angered the Jade Emperor in heaven because the crane was his favorite. So, he planned a storm of fire to destroy the village on the fifteenth lunar day. The Jade Emperor's daughter warned the inhabitants of her father’s plan to destroy their village. The village was in turmoil because nobody knew how they could escape their imminent destruction. However, a wise man from another village suggested that every family should hang red lanterns around their houses, set up bonfires on the streets, and explode firecrackers on the fourteenth, fifteenth, and sixteenth lunar days. This would give the village the appearance of being on fire to the Jade Emperor. On the fifteenth lunar day, troops sent down from heaven whose mission was to destroy the village saw that the village was already ablaze, and returned to heaven to report to the Jade Emperor. Satisfied, the Jade Emperor decided not to burn down the village. From that day on, people celebrate the anniversary on the fifteenth lunar day every year by carrying lanterns on the streets and exploding firecrackers and fireworks.

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