One of the things the Romans are most famous for is their architecture. And it’s true that the Romans brought a lot of new ideas to architecture. The three most important ideas are the arch, the baked brick, and the use of cement and concrete.
Around 700 BC, Etruscans and Carthaginians brought West Asian ideas about architecture to Italy. They taught these ideas to the Romans. We don’t have much Etruscan architecture left, but a lot of their underground tombs do survive, and some traces of their temples.
In the Republican period, the Romans built temples and basilicas, but also they made a lot of improvements to their city: aqueducts and roads and sewers. These buildings and roads paralleled the ones being built at the same time in China and India, in West Asia, in North Africa, and in South America.
The Forum began to take shape. Outside of Rome, people began to build stone amphitheaters for gladiatorial games. The first Roman emperor, Augustus, made more changes: he built a lot of brick and marble buildings, including a big Altar of Peace and a big tomb for his family, and a big stone theater for plays. Augustus’ stepson Tiberius rebuilt the Temple of Castor and Pollux in the Roman forum.
Augustus’ great-great-grandson Nero also did a lot of building in Rome, including his Golden House. Then in 69 AD Vespasian tore down some of the Golden House to build the Colosseum. Vespasian’s son Titus built a great triumphal arch, and his other son Domitian built a great palace for himself on the Palatine hill.
Even though Domitian’s cousin killed him in 96 AD, later architects kept on using the techniques that had been developed for his palace, just as later emperors continued to live in Domitian’s palace. Trajan’s architect used brick and concrete arches to build a new forum with a big column in it and an elaborate market building that is the source of modern shopping malls. Trajan also built the first major public bath building in Rome. It may have been the same architect who later designed Hadrian’s Pantheon, a temple to all the gods, which used brick and concrete to build a huge dome. Nobody would build a bigger dome for more than a thousand years.
In the provinces of the Roman Empire, people were also building forums, temples, bath buildings, amphitheaters and apartment blocks. But generally they built them smaller than buildings in Rome. There are many well-preserved Roman cities around the Roman Empire. In Italy, there’s Pompeii, Ostia, and Cosa. Going eastward around the Mediterranean, there are well-preserved Roman towns in Turkey at Ampurias, and in Israel at Caesarea. In North Africa, there are Roman cities in Libya at Lepcis Magna, and in Tunisia at Bulla Regia, Dougga, and Maktar. Further west, there are Roman towns in Morocco at Volubilis, and in Spain at Italica and Empurias.
After Hadrian, there was no more money coming in from conquest and plunder. So the Romans had to cut back a bit on their building programs. Still, the emperor Caracalla built a great bath building in Rome in the early 200s AD. And in the late 200s the emperor Diocletian built another. In the early 300s AD, the emperor Maxentius built a great imperial palace outside the walls of Rome, and a basilica in the Roman Forum. Constantine built a triumphal arch, and a series of Christian churches. But then he transferred the capital of the Roman Empire to Constantinople (Istanbul) where he, and his successors, built many more churches, circuses, and palaces.