The Pantheon: still the world’s largest unreinforced concrete dome
The Pantheon in Rome, now a church, was built as a temple to all the gods. It has been a shrine for architects since the Renaissance. It is also a worthy tribute to the skills of the ancient Roman masons and engineers who built it and the incredible alchemy of their concrete mix.
Commissioned by Hadrian (who was emperor 117-138 CE) as a temple to all the gods, the Pantheon replaced Agrippa’s earlier temple following a fire. It is still the most visited site in Italy, having weathered centuries of tourists, floods, wars and earthquakes.
Its huge concrete dome – 43.4m in diameter and 21.75m high – was unrivalled in size until the building of Florence Cathedral in the 1400s, and is still the largest ever made with unsupported concrete.
“The mastery of building something so daring and having the structure resist essentially without any structural support for more than 19 centuries is simply extraordinary,” says Renato Perucchio, professor of mechanical engineering and director of the Archaeology, Technology, and Historical Structures Programme at the University of Rochester in the US.