A pentagonal artillery battery known as the Low Battery is grafted below the walls at the easternmost extremity of the fortress, close to St. John's Demi-Bastion. The southern perimeter of the Cittadella is surrounded by a ditch, which originally extended from St. Martin's Demi-Bastion to the Low Battery but now begins at St. Michael's Bastion due to 19th-century alterations. A covertway with a single place-of-arms runs along the ditch. A steep glacis was located outside the covertway, but this has been built up. A small triangular ravelin stands near the entrance to the city, but this has lost most of its original stonework and has been converted into a garden, losing its legibility as part of the fortress in the process.