On a typical second-century day, the sun would rise on Han China, pass over the Buddhist stupas of Mauryan India, glare down on the brick ruins of the Indus and Euphrates valleys, and take more than two hours to traverse the Roman lake of the Mediterranean. By the time it was noon at Gibraltar, worshippers would be greeting the dawn from the tops of pyramids in highland Mexico, the Guatemalan jungle, and the irrigated valleys of Peru.
