Porta Marina - Pompeii - The most imposing of the seven gates of Pompeii. It takes its name from the fact that the road lead to the sea. It has two barrel arches, later converted into a single barrel vault.
Trier, Germany. This was once the capital of the Roman Empire. It is the oldest city in Germany. In the picture is the Porta Nigra, The Black Gate. It is the only gate left standing in this once walled city.