One of the first Thanksgiving celebrations was in 1621, when the Plymouth colonists and the Wampanoag shared an autumn harvest feast.

Pilgrims held their second Thanksgiving celebration in 1623 to commemorate the end of a long drought that had threatened the year's harvest and prompted Governor Bradford to call for a religious fast. Days of fasting and thanksgiving on an annual or occasional basis became common practice in other New England settlements as well.

For more than two centuries, days of thanksgiving were celebrated by individual colonies and states, and it wasn't until 1863, in the midst of the Civil War, that President Abraham Lincoln proclaimed a national Thanksgiving Day to be held each November.

In many American households, Thanksgiving has lost much of its original religious significance; it now centers mostly on cooking and sharing a bountiful meal with family and friends. When it comes to turkey, a Thanksgiving staple so ubiquitous it has become an essential part of the holiday, we aren't sure if it was or wasn't served when the Pilgrims hosted the inaugural feast in 1621.

But today, 85 to 90 percent of Americans prepare the bird—whether roasted, baked or deep-fried—on Thanksgiving. Other traditional foods include stuffing, mashed potatoes, cranberry sauce and pumpkin pie. Volunteering is a common Thanksgiving Day activity, and communities often hold food drives and host free dinners for the less fortunate.

Although the American concept of Thanksgiving developed in the colonies of New England, you could theoretically trace its roots back to the other side of the Atlantic. Both the Separatists who came over on the Mayflower and the Puritans who arrived soon after brought with them a tradition of providential holidays—a time of fasting during difficult or pivotal moments and days of feasting and celebration to thank God in times of plenty.

Imagine the memes they'd share!