Thanksgiving is a federal holiday in the United States celebrated on the fourth Thursday of November (which became the uniform date country-wide in 1941). The earliest Thanksgiving can occur is November 22; the latest is November 28. Outside the United States, it is called American Thanksgiving to distinguish it from the Canadian holiday of the same name and related celebrations in other regions. The modern national celebration dates to 1863; prior to this, it was a regional holiday, whose origins lie in the 17th and 18th century days of thanksgiving of Calvinist New England. The evolution of the holiday was not linear (various New England communities had independently developed their own similar traditions that were slowly harmonized into a singular annual Thanksgiving Day); the first known civil day of thanksgiving in the New England tradition was declared at Plymouth Colony in 1623, two years after the famous 1621 harvest celebration popularized as the "first Thanksgiving" bearing substantial, if coincidental, similarity to what Thanksgiving Day would eventually become. Celebrations of thanksgiving for the harvest in New England became a regular occurrence by the 1660s. As the name implies, the theme of the holiday generally revolves around giving thanks and the centerpiece of most celebrations is a Thanksgiving dinner with family and friends. The dinner often consists of foods associated with New England harvest celebrations: turkey, potatoes (usually mashed and sweet), squash, corn (maize), green beans, cranberries (typically as cranberry sauce), and pumpkin pie. It has expanded over the years to include specialties from other regions of the United States, such as macaroni and cheese and pecan pie in the South and wild rice stuffing in the Great Lakes region, as well as international and ethnic dishes. Other Thanksgiving customs include charitable organizations offering Thanksgiving dinner for the poor, attending religious services, and watching or participating in parades and American football games. Thanksgiving is also typically regarded as the beginning of the holiday shopping season, with the day after, Black Friday, often considered to be the busiest retail shopping day of the year in the United States. Cyber Monday, the online equivalent, is held on the Monday following Thanksgiving.