This important occasion is one of the 3 "pilgrimage" festivals which is commanded to be observed in the Old Testament Book of Leviticus (Chapter 23).
Several names besides Feast of Tabernacles are given to this holiday including Feat of Booths, Sukkot, Feast of Nations, and Season of Our Joy.
During this Feast, the Jewish people are instructed to live in booths (little outdoor structures that are made in a special way.)
The picture above of a typical booth (Sukkot) made from wood is by Effi B. and was posted on the Wikimedia Commons site.
For details about this very important event, HERE'S A LINK
and HERE'S ANOTHER
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