Boats are moored in the waters by Plymouth Rock in Massachusetts, USA. A nearby site onshore is recognized as the disembarkation point of William Bradford and the Mayflower Pilgrims who founded Plymouth Colony in 1620. The following year, they celebrated a successful harvest with a three-day event that was attended by members of the Wampanoag Tribe. It’s from this gathering that we derive the modern Thanksgiving celebration as we know it.