Lasting eight days, Sukkot commemorates the Israelites' wanderings in the desert following their exodus from Egypt. As they traveled, they lived in portable shelters. Sukkot also has an agricultural significance, coinciding with the autumn harvest season and celebrating the earth's bounty.
For many, this holiday is celebrated by building, eating in and sleeping in a sukkah and waving tree branches, specifically a palm branch, three myrtle branches and two willow branches, (put together, called the lulav) and a lemon-like fruit called a citron (called etrog in Hebrew). The customs of dwelling in a sukkah and shaking the lulav and etrog are ancient and derived from Biblical references.
As the holiday comes to a close, the celebration continues for two more days. Shmini Atzeret, the Eighth Day of Celebration, begins.
The conclusion of this festive season takes place with the mega-celebration of Simhat Torah, the Festival of Rejoicing in the Torah. On Simhat Torah, amidst yet more singing and dancing, Jews read the final passages of the Torah (the Five Books of Moses) and then go all the way back to the beginning to start reading it again. If the weather is nice, the celebration and dancing spills outdoors.
These harvest time festivals are a time of spiritual uplift and an appreciation of the natural world.