The Acqua Claudia, Rome (AD 38) was build by the Emperors Caligula and Claudius and carried water to Rome from Subiaco, 45 miles away. In part it rests on solid masonry but across the Campagna it is carried on tall arches for some 9.5 miles. Finest of the Roman aqueducts, some of its arches exceed 100 feet in height. Great lengths of its structure survive in the Campagna and it is to these Ruskin refers, comparing his recollection of the scene with Gaspar Poussin 's rendering of it.