Eternal Rome, Italy's capital
The Porta San Giovanni, a gate in the Aurelian Wall, named after the nearby Basilica di San Giovanni in Laterano. It is made up of a single grand arch built for pope Gregory XIII and was inaugurated in 1574. The Aurelian Wall is a line of protective city walls built between 271 and 275 CE during the reign of Emperors Aurelian and Probus in response to the threat from Germanic tribes near the borders of the Roman Empire. It was originally 19 kilometres long, about 6 metres high and 3.5 metres thick with a square tower about every 30 metres.