Resembling a crenellated keep, Porta Settimiana marks the start of Via della Lungara, the 16th-century road that connects Trastevere with the Borgo. It was built in 1498 by Pope Alexander VI over a small passageway in the Aurelian Wall and later altered by Pope Pius VI in 1798. From Porta Settimiana, Via Santa Dorotea leads to Piazza Trilussa, a hangout popular with revellers in the evening, and Ponte Sisto, which connects with the centro storico (historic centre).