About a 1km (15-minute) walk south down St Michael’s Rd from the top cable-car station, O’Hara’s Rd leads up to the left to O’Hara’s Battery, an emplacement of big guns on the Rock's highest point, within the Upper Rock Nature Reserve.
Since the early 20th century, the battery has hosted a 9.2in gun with a range of over 16 miles – hence the nickname.