'For walls & vaults, the Romans invented a superior type of this material made of cement, water & gravel'
Concrete
OF THE ROMAN EMPIRE: For walls & vaults, the Romans invented a superior type of this material made of cement, water & gravel
For walls & vaults, the Romans invented a superior type of this material made of cement, water & gravel
For walls & vaults, the Romans invented a superior type of this material made of cement, water & gravel
OF THE ROMAN EMPIRE
Concrete
OF THE ROMAN EMPIRE