For the other world event, similar to the North American holiday, Thanksgiving, see Pilgrim's Bounty.
During the Harvest Festival of Azeroth, the Horde and the Alliance give thanks to heroes for the sacrifices - in some cases ultimate sacrifices - they have given on our behalf. In the time of the Harvest Festival, a great buffet is built up outside of Ironforge and Orgrimmar.
Throughout history, many have given their lives to aid their allies. Every year, members of the Horde and the Alliance set aside time to honor the memories of the fallen and to pay tribute to those whose memories are held most dear: Uther Lightbringer, for the Alliance, and Grom Hellscream, for the Horde. Heroes take time from their adventures to visit the graves of these two great leaders and to leave a tribute to them at the memorial. To show their respect, members of the Alliance light a candle at the Tomb of Uther Lightbringer in the Western Plaguelands. Members of the Horde show their respect to Grom Hellscream by leaving a bottle of spirits at the base of the Hellscream Memorial in Demon Fall Canyon in Ashenvale.
Outside of Orgrimmar and Ironforge are a table and wandering ghostly NPCs of the corresponding faction, fallen heroes, who can be waved or cheered at, saluted and bowed before.
The following items can be picked up from the table:
Additionally, 2 days later after completing either quest, the player gets [Bounty of the Harvest] in the mail. It is an item with a 12 hour cooldown which produces 4 food from the harvest.
Notes
It is likely that, similar to Lunar Festival, Harvest Festival is an in-game event corresponding to harvest festivals in East Asia, such as the Chinese Mid-Autumn Festival and the Korean Chuseok as the dates generally coincide
Coincides with the anniversary of Stress Test Beta Has Ended. The final day is Columbus Day in the United States and Thanksgiving Day in Canada (October 8th in 2007).