 Cultures who built substructure mounds include the Troyville culture, Coles Creek culture, Plaquemine culture and Mississippian cultures.The 27-metre-high Pyramid of Cestius was built by the end of the 1st century BC and still exists today, close to the Porta San Paolo.Another one, named "Meta Romuli", standing in the "Ager Vaticanus" (today's Borgo), was destroyed at the end of the 15th century.