article_snippet: The walls of the buildings in the largest earthen city in pre-Columbian America were often decorated with intricate friezes representing abstract motifs .
article_snippet: The walls of the buildings in the vast city the buildings in the vast city were often decorated with intricate friezes representing abstract motifs, although the fragile nature of the earthen structures mean the site is slowing-but-surely eroding, so get there soon if you can.