13. The Ancestral Puebloans (Anasazi)
The Ancestral Puebloans, often called the Anasazi, constructed awe-inspiring cliff dwellings at sites like Chaco Canyon and Mesa Verde. In the late 13th century, these remarkable settlements were abandoned with surprising speed. Most experts believe a lengthy drought and dwindling natural resources forced communities to leave their homes behind. The sudden desertion transformed once-bustling centers into silent ruins, their intricate structures now a testament to both ingenuity and vulnerability. Read more at the National Park Service.
