23 November 2011
Last updated at 19:01 ET
In October 1789, President George Washington proclaimed Thursday 26 November of that year "a day of public thanksgiving and prayer". He made no mention of turkey - or any other food - but the native bird has long been associated with the holiday. This boy, photographed between 1910 and 1915, carries one home.
Today, nearly 88% of Americans eat turkey on Thanksgiving, according to the National Turkey Federation. Some of those, like the birds shown above, come from Willie Bird Turkey Farm in Sonoma, California.
Americans eat about 46 million turkeys during the holiday season. In recent decades, it has become a tradition for the president to "pardon" a bird, sparing it from death.
The holiday's cultural importance makes it a ripe opportunity for protest. Last year, Julia Botello, 84, ate a Thanksgiving meal at the doorstep of a bank in Long Beach, California with homeowners facing eviction.
The day after Thanksgiving is one of the busiest shopping days of the year. Called Black Friday, because it's the day some retailers begin to book a profit on the year, it is the traditional start of the holiday shopping season. Some queue up before dawn for what they hope will be the best bargains.
Large, middle-market department stores like Macy's, above, in New York City, are packed full of shoppers.
The Thanksgiving holiday is also a time for charity toward those less fortunate. Last year, President Obama and his mother-in-law, Marian Robinson, right, distributed bags of food at Martha's Table, a Washington DC food pantry.
Across America on Thursday, churches, charities and food pantries feed homeless and destitute Americans a hot meal.
During the Great Depression, social service agencies delivered tons of food to impoverished Americans, including this elderly New York woman, shown on 7 November 1930.
The Thanksgiving meal, with its connotations of home, family and comfort, has been a crucial part of military life for US soldiers from the Civil War onwards.
It is also a day soldiers mark by holding sport matches, as here in Afghanistan.