Question: what material was used to build the colosseum?
Answer: The Colosseum: A Grand Amphitheater Measuring some 620 by 513 feet (190 by 155 meters), the Colosseum was the largest amphitheater in the Roman world. Unlike many earlier amphitheaters, which had been dug into hillsides to provide adequate support, the Colosseum was a freestanding structure made of stone and concrete.