Ancient Ceremonial Plaza Found in Peru

German and Peruvian archeologists work at the circular 5,500-year-old sunken ceremonial plaza, built of stones and adobe, part of the Sechin Bajo archaeological complex in Casma, Andes foothills, 330 kilometers (206 miles) northwest of Lima, Feb. 2008. The archeologists say the plaza is the oldest known monument in Peru. (AP Photo/ El Comercio)