Stone structures like this dot the desert Southwest. The people who constructed them date to the early 21st century or possibly the middle-to-late 20th century and probably had cultural—if not biological—connections to the builders of nearly identical stone rings in other parts of North America. We know from artifacts scattered at these sites that the stonework was associated with the consumption of manufactured food and alcoholic beverages. Ashes inside the masonry rings might be from cooking fires, though it is believed actual cooking had fallen out of fashion by the time of these ruins. Others believe the fires were used primarily for ceremonial and social purposes instead. A third hypothesis suggests the ashes are from roofs that once covered the structures. Some sites are littered with spent ammunition which may be from battles over territorial rights. Such battles might explain the burned roofs.