Ancient Roman Supplement.

Arch. The ancient Romans built their arches beginning with the keystone and building outward from there. The very last course of bricks or stones was the one that connected the arch with the ground.

Colosseum. The Colosseum, or Flavian Amphitheater, was built originally as an indoor shopping mall (the Venalicium Flavianum). Disappointing retail performance persuaded the emperor Titus to find another use for the complex.

Florianus. Coins of the emperor Florianus depict him wearing what puzzled numismatists describe as a kind of sombrero.

Nero. Although long tradition says that Nero fiddled while Rome burned, historians have now established conclusively that he actually played a primitive sort of harmonica.

Pantheon. Although the Pantheon was supposed to have been dedicated to all the gods, it was discovered during the reign of Caracalla that three minor deities had been left out. The embarrassing omission was never rectified, but several priests were secretly executed for their error.

Pertinax. The emperor Pertinax was the first Roman emperor to hop on one foot for more than three hours straight. Historians estimate that his accomplishments would have been even greater had his reign lasted longer than three months.

Via Appia. Archaeologists excavating along the shoulder of the famous Via Appia have discovered a four-foot obelisk bearing the remains of painted decoration in alternating horizontal stripes of white and orange. So far, no one has been able to determine the purpose of the object.