The walls of Anagni are wonderful only as the great works of Rome are wonderful. They are built by men to whom it was more natural to put together rectangular stones with some kind of regularity than it was to pile together huge polygons anyhow. They were built by men who thoroughly understood the principle of the arch, and knew how to use it with all boldness. They remain, in various degrees of preservation, round the greater part of the circuit of the town. In some parts they are broken down altogether; in some they are supplanted, in others merely patched, by walls of later date; in short, they have gone through all the casualties which a wall is likely to go through in the course of two millenniums or so; but the wall of modern Anagni, as a whole, is still the old wall of Anagnia. The construction differs a good deal in different parts as to the size of the stones and as to their nature, and as to the degree of rudeness or finish in the work. In some parts the wall stands single; in others it is strengthened by further defences, buttresses rather than towers--defences, by-the-way, which must be carefully distinguished from the additions of later times. But one general character reigns throughout. The stones, greater and smaller, smoother and rougher, are always rectangular, and always laid with some measure of regularity. In some cases ranges of larger and smaller stones alternate; in one part of the wall stones of two natures and colours almost alternate. The chief material is a light-coloured stone exactly like the _puff-stone_ of Gloucestershire, the material of Berkeley Castle and of not a few other buildings in that neighbourhood. This is eked out here and there by the dark volcanic _peperino_, which, towards the south-eastern part of the wall, is used much more freely. The general effect, wherever the wall is at all perfect, is stately and striking in the extreme, both in form and colour.