[Illustration: RUINS OF THE COLOSSEUM] TWO FAMOUS BUILDINGS. Many of the Roman temples, porticoes, and theaters were copied from Greek buildings, but the Romans used the arch more than did the Greeks, and in this the builders of later times imitated them. Among their greatest buildings were the amphitheaters, from the benches of which crowds watched gladiators fighting one another or struggling with wild beasts. The largest of these amphitheaters was the Colosseum, the ruins of which still exist. Its outer walls were one hundred and sixty feet high. In one direction it measured six hundred and seventeen feet and in another five hundred and twelve. There were seats enough for forty-five thousand persons. The lowest seats were raised fifteen feet above the arena or central space where men or wild beasts fought. Through an arrangement of underground pipes the arena could be flooded so that the spectators might enjoy the excitement of a real naval battle. Another great building was the Circus Maximus, built to hold the crowds that watched the chariot-races, and at one time having seats for two hundred thousand persons. In their amusements the Romans became more and more vulgar, excitable, and cruel. Some equally splendid buildings were used for better things. [Illustration: The Pantheon] THE PANTHEON. One of these was the Pantheon, a temple which was afterward a Christian church. It still stands, and is now used as the burial-place of the Italian kings. The most remarkable part of it is the dome, which has a width of a little over one hundred and forty-two feet. No other dome in the world is so wide. The Romans were very successful in covering large spaces with arched or vaulted ceilings. All later builders of domes and arches are their pupils. [Illustration: THE ARCH OF TITUS] BASILICAS. The Romans had other large buildings called basilicas. These were porticoes or promenades, with the space in the center covered by a great roof. They were used as places for public meetings. One of them had one hundred and eight pillars arranged in a double row around the sides and ends of this central space. The name basilica is Greek and means "royal." Some of these basilicas were used as Christian churches when the Romans accepted the Christian religion. The central space was then called the "nave," and the spaces between the columns the aisles. TRIUMPHAL ARCHES. The Romans built beautiful arches to celebrate their victories. Several of these still remain, with sentences cut into their stone tablets telling of the triumphs of their builders. Modern people have taken them as models for similar memorial arches. [Illustration: A ROMAN AQUEDUCT Still in good repair, the Pont du Gard, near Nimes, France]