what was the largest dome in the world built by the romans
1 The Pantheon in Rome is another famous Roman building, built as a temple. 2  It still has the worldâs largest unsupported concrete dome, which measures almost 10 metres across. 3  The Romans built many roads, bridges and aqueducts to expand their empire. The Pantheon in Rome is another famous Roman building, built as a temple. 2  It still has the worldâs largest unsupported concrete dome, which measures almost 10 metres across. 3  The Romans built many roads, bridges and aqueducts to expand their empire.