Flat Bastion The Flat Bastion is a bastion which projects southward from the Charles V Wall in the British Overseas Territory of Gibraltar . At one time known as St . Jago ' s Bastion or the Baluarte de Santiago in Spanish , its construction was begun by the Spanish in the mid 16th century . The fortification formed part of the southern defences of the city of Gibraltar , together with Charles V Wall and , to its west , Southport Gate , Southport Ditch , and South Bastion . Flat Bastion takes its name from the angle that its south - facing walls form with each other and with the Charles V Wall . Within the eastern portion of the Flat Bastion is the Flat Bastion Magazine . The bastion and magazine within it are separately listed with the Gibraltar Heritage Trust . The magazine has been restored and converted into a research facility . History . The Flat Bastion " ( outline pictured in map at right ) " is a fortification in Gibraltar , the British Overseas Territory at the southern end of the Iberian Peninsula . Its north end is along the Charles V Wall , from which it projects southward . The Prince Edward ' s Gate , Prince Edward ' s Road , and Trafalgar Cemetery are just to the west of the bastion " ( see maps below and at right ) " . Flat Bastion Road extends to the bastion at the east side of its north face at the Charles V Wall and traverses the bastion . The road becomes Gardiner ' s Road at the south face of the bastion on its east side " ( see map below ) " . During the first quarter of the 16th century , a new type of military fortification emerged in northern Italy . It addressed the long - standing issue of " dead ground " near a fortress in which an opponent could hide . The fortification that was developed to resolve this problem was the angle bastion . This type of fortress was an angular , arrowhead - shaped projection from the line of a curtain wall . The bastion featured two faces and two flanks ( sides ) . Cannons positioned on the flanks of a bastion could fire upon the ground adjacent to the curtain wall as well as that along the face of a nearby bastion , giving assailants no place to hide . To further protect the bastion , it was surrounded by a wide ditch , as well as a glacis " ( pictured below ) " , the large area of cleared ground outside of the ditch which sloped up toward the bastion . The earth excavated from the ditch was also used in construction to fortify the bastion , absorbing the impact of gunfire . The Spanish began construction of the Flat Bastion in the 16th century , in 1552 , at which time it was referred to as St . Jago ' s or Santiago ' s Bastion ( ) . Professor Clive Finlayson , Director of the Gibraltar Museum and the Heritage Division , indicated that the flat bastion was built by 1627 . He speculated that Daniel Specklin may have designed it , as its outline was essentially identical to that in the architect ' s book , including the presence of a retired flank " ( pictured at lower edge of map at right ) " . An earlier , 1608 map of Gibraltar by Cristóbal de Rojas includes the Flat Bastion and the South Bastion . However , England claimed that Spain had never finished the construction of the Flat Bastion . In 1859 , six guns , four 12 - pounders and two 12 - pound carronades , were installed on the bastion . Four years later , in 1863 , five 32 - pounders were mounted on the fortification . The earliest defences of the southern end of the city of Gibraltar included the sixteenth century Charles V Wall , Flat Bastion , South Bastion , Southport Gate , and Southport Ditch . The Flat Bastion and the South Bastion ( ) were elements in the defence of the Africa Gate ( ) , now referred to as the Southport Gate . Both the Southport Gate and the adjacent Southport Ditch , labeled as " Puerta de Africa " and " Fosso " , respectively , are depicted in a 1627 map of Gibraltar . The Southport Gate is the smallest of a trio of gates , west of the Flat Bastion and adjacent to Trafalgar Cemetery , that are known as the Southport Gates " ( pictured below ) " . That smallest gate was the first of the three and was constructed by engineer Giovanni Battista Calvi at the same time that he designed the Charles V Wall , in 1552 . The gate in the middle of the trio is ornamented with the arms of Queen Victoria and Governor of Gibraltar General Sir John Miller Adye and was built in 1883 . The third gate is the largest and was constructed in 1967 . Entitled the Referendum Gate , it commemorates the votes cast by Gibraltarians in the sovereignty referendum of 1967 . The Southport Gates are listed with the Gibraltar Heritage Trust . The name of the bastion refers to the faces of the fortification and not to the slope of the ground on which it was built . The Flat Bastion was constructed on sloping ground . A 1908 map of the Flat Bastion confirms that its south faces join at an obtuse angle which is relatively flat , and nearly parallel the Charles V Wall " ( pictured on map above ) " . Finlayson indicated : " The Baluarte de Santiago is a flat bastion , with its faces almost parallel to the curtain wall on either side . " The Flat Bastion includes the Flat Bastion Magazine within its eastern portion . The latter is now a geological research and exhibition facility . The bastion is a listed building with the Gibraltar Heritage Trust . While St . Jago ' s Bastion has been said to be an early name for the Flat Bastion , it has a separate listing with the Gibraltar Heritage Trust , next to those for the Flat Bastion and Flat Bastion Magazine . The complex of defences also included Southport Ditch which was depicted in the 1627 map of Gibraltar by engineer Luis Bravo de Acuña . On that map which is held by the British Museum , the ditch is shown as a " Fosso " south of Southport Gate . It was a large trench which extended from the southwestern aspect of the sixteenth century South Bastion to the Flat Bastion at Prince Edward ' s Gate . The width of the ditch is now indicated by that of Ragged Staff Gates , which were initially a water gate . By the late nineteenth century , the ditch was utilised as an ordnance depot , with a magazine constructed in the 1880s . However , by the early twentieth century , that same magazine was used as a pump house , as confirmed on a 1908 OS map . After World War I and reclamation of land , the Ragged Staff Gates were opened to vehicular traffic . Gibraltar ' s Sunken Gardens , a nineteenth - century market garden , were a remnant of the western portion of the Southport Ditch , and were filled in at the time of the 1967 Referendum Gate . Trafalgar Cemetery represents an eastern remnant of the ditch . Flat Bastion Magazine . The 1908 Ordnance Survey map also reveals the Flat Bastion Magazine within the east side of the bastion " ( above ) " . The British version of the magazine dates back to at least 1873 , as documented above one of the magazine ' s doorways " ( pictured at right ) " . It is considered likely that a magazine was present at that site previously . The magazine was constructed on scree breccia , with underlying limestone bedrock . The road through the bastion is positioned just to the west of the magazine . The British magazine was constructed to store about five thousands barrels of gunpowder . The main area has been described as a " room within a room " as it is surrounded by a narrow hallway . Numerous wood supports are still present in the magazine . The walls of the magazine were built with bricks to help absorb the impact of explosions . In addition , the oak doors of the magazine date back five or six centuries , well before the British version of the magazine . Flat Bastion Magazine had been abandoned for years when Freddie Gomez undertook its restoration . Gomez , whose interests include both history and geology , converted the magazine to a geological research facility and exhibition centre . While much of the contents of the large collection of rocks and minerals are from his collection , other specimens have been donated . The men of the 150 ( Yorkshire ) Transport Regiment also spent a day performing repairs at the magazine . Gomez aspires to open the site to the public . The Gibraltar Heritage Trust has presented the Gibraltar Heritage Award annually since 1993 . In 2001 , the restoration of the Flat Bastion Magazine earned Gomez the 2001 award for " his enthusiasm and single - minded dedication to the restoration and preservation of Flat Bastion Magazine . " The Flat Bastion Magazine is also listed with the Gibraltar Heritage Trust ( in addition to the listing for the bastion itself ) . Prince Edward ' s Gate . Prince Edward ' s Gate " ( link to map below ) " extends from the northwest corner of the bastion and overlooks Trafalgar Cemetery to the southwest and the former St . Jago ' s Cemetery to the northwest . It was constructed adjacent to the retired flank and behind the orillon of the bastion ' s west wall , which aided in the gate ' s defence . This is demonstrated at the lower edge of the 1908 OS map " ( above ) " . The gate was named after Prince Edward , Duke of Kent and Strathearn . The prince was the fourth son of the King George III and , later , the father of Queen Victoria . At the time that the gate was opened in the Charles V Wall , in 1790 , the prince was serving with the military in Gibraltar . He later returned as Governor of Gibraltar in 1802 . Despite leaving Gibraltar the following year , the Duke declined to resign the governorship . Subsequently , a series of lieutenant governors served until the Duke ' s death in 1820 . The Prince Edward ' s Gate is listed with the Gibraltar Heritage Trust .