On the fourth Thursday in November, US citizens celebrate Thanksgiving Day. History reveals that for the first few years after the English pilgrims made their home in the New World, they were beset by famine and cold—surviving only through the assistance of friendly Native Americans. And so when they were finally able to have a plentiful harvest in 1621, they celebrated Thanksgiving as a way of remembering both the blessings and the hardships they’d endured.