The Aurelian Walls are the longest and best preserved Ancient Walls of Europe and out of the original 19 kilometers (12 miles) 12 kilometers are still intact (8 miles). They were built by the Emperor Aurelian and later reinforced by the Eastern Emperor Honorius to keep the Goths out. Honorius doubled the height of the walls which were 11 feet thick and 24 high, every thirty meters there was a watch tower with a ballista on it, 381 in total, 18 main gates flanked by smaller gates and 114 latrines.
Later the gate took the name of a soldier which suffered martyrdom, St. Sebastian. The museum opened in 1990 even if already in 1940-43 underwent some major restorations to become the alcove of the fascist secretary Ettore Muti. The black and white mosaic on the first floor connecting the two towers dates back to his time. The view from the windows of the first level is already worth the climbing: on one side the Arch of Drusus, part of an Ancient Aqueduct (Aqua Antoniniana) which once fed the Caracalla's Baths, and the villas on the Appian Way on the other side.
In 1327 the gate became scene of struggles between the two parties supporting the Pope (Guelphs) and the king of Naples (Ghibellines) and when the Papal party won, the Archangel Michael defeating a dragoon was engraved in the inner part of the central gate.
From the first level, a small draft door will take you to the most fascinating part of the walls: the ancient covered walkway where the arches are lined in a unique geometric perfection.
In one of the watchtower you will find a fresco of a Madonna apparently memory of a romitorio, the simple refuge of a hermit. The walls suffered collapses and damages for the erosion of elements, and some of the steps were restored with ancient recycled marbles. From the top of the walls, you can taste a fantastic view over the roman countryside part of the Regional Park of the Appian Way.
Tips: The bike is the best way to taste this part of Rome, especially on Sunday when the Appian Way is pedestrian. Always bring with you a U-lock to tide the bikes to a tree or a road sign while visiting sights during the way.
Bus number 118 is the buses which will take you here from the Colosseum.
The Museum of the Walls is opened every day except on Monday from 9 to 14. It is free of charge.
From here you can also visit the Catacombs on the Appian Way, the Caracalla's Baths, Villa of the Quintilii.
If you need any further information, contact me through http://www.mylovelyrome.com