On the north coast of Africa lie the ruins of a city that came within a hairbreadth of defeating the might of Rome. Now archaeologists digging at the famous Circus of Carthage have revealed a startlingly advanced system to cool down horses and chariots during races... Key to the discovery of the clever cooling system at the Circus of Carthage, the biggest sporting arena outside Rome, was the detection of water resistant mortar... The discovery was made at the spina, the median strip of the circus, around the ends of which the charioteers would turn during races. The spina would...