The Alhambra which translates "the red fortress" was constructed during the mid 14th century as a palace and fortress by the Moorish rulers in Granada, Spain. It is most famous for its Islamic architecture.

Alhambra

The Alhambra which translates "the red fortress" was constructed during the mid 14th century as a palace…

The Alhambra is a palace and fortress complex of the Moorish rulers of Granada in southern Spain.

The Alhambra

The Alhambra is a palace and fortress complex of the Moorish rulers of Granada in southern Spain.

"The amphitheater was made a fortress, packed with houses, in the eighth century, on account of Saracen incursions."—Myers, 1905

The Amphitheater at Arles

"The amphitheater was made a fortress, packed with houses, in the eighth century, on account of Saracen…

The Bastille, a fortress-prison in Paris remembered by the storming of the Bastille in the French Revolution.

Bastille

The Bastille, a fortress-prison in Paris remembered by the storming of the Bastille in the French Revolution.

The storming of a medieval fortress and prison in Paris by revolutionaries, which represented royal authority.

Storming of the Bastille

The storming of a medieval fortress and prison in Paris by revolutionaries, which represented royal…

A quickly made fortress used as a temporary means of defense.

Block House

A quickly made fortress used as a temporary means of defense.

The Walls of Carcassonne are what fortify the French town of Carcassonne in France. It was fortified on a hilltop by the Romans in 100 BC.

Walls of Carcassonne

The Walls of Carcassonne are what fortify the French town of Carcassonne in France. It was fortified…

"This fortress was founded by Edward I in 1283. It is one of the most impressive of the decayed medieval strongholds of the British Isles."—Myers, 1905

Carnarvon Castle

"This fortress was founded by Edward I in 1283. It is one of the most impressive of the decayed medieval…

An illustration of a castle.

Castle

An illustration of a castle.

The Cathedral Church of Christ, Blessed Mary the Virgin and St Cuthbert of Durham, commonly referred to as Durham Cathedral, in the city of Durham, England, was founded in AD 1093 and remains a centre for Christian worship today. Durham Castle is a Norman castle in the city of Durham, England, which has been wholly occupied since 1840 by University College, Durham. The castle stands on top of a hill above the River Wear on Durham's peninsula, opposite Durham Cathedral.

Durham Cathedral and Castle

The Cathedral Church of Christ, Blessed Mary the Virgin and St Cuthbert of Durham, commonly referred…

Also known as the Castle of St. Angelo. A castle is a defensive structure seen as one of the main symbols of the Middle Ages.

Hadrian's Castle, Rome

Also known as the Castle of St. Angelo. A castle is a defensive structure seen as one of the main symbols…

The palais du Louvre in Paris, on the Right Bank of the Seine is a former royal palace, situated between the Tuileries Gardens and the church of Saint-Germain l'Auxerrois. Its origins date back to the medieval period and its present structure has evolved in stages since the sixteenth century.

Plan of Louvre and Tuileries, Paris

The palais du Louvre in Paris, on the Right Bank of the Seine is a former royal palace, situated between…

A detached triangular work in fortification, with two embankments which form a projecting angle. In the figure B B is the ravelin with A its redout, and CC its ditch, DD being the main ditch of the fortress,and E the passage giving access from the fortress to the ravelin.

Ravelin

A detached triangular work in fortification, with two embankments which form a projecting angle. In…

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place when within range of fire. This is a section of covered sap.

Covered Sap

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place…

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place when within range of fire. This is a double sap on the serpentine plan.

Double Sap

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place…

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place when within range of fire. This is sap on a rectangular plan.

Rectangular Sap

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place…

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place when within range of fire. This is a section of single sap, showing portion of gabions.

Single Sap

In military affairs, a narrow ditch or trench by which approach is made to a fortress or designed place…

This image depicts a man and a donkey walking under The Tower of Justice, the original entrance gate to the Alhambra. The Alhambra is a fortress in Granada, Spain that was built in 1348 by Yusuf I.

The Tower of Justice

This image depicts a man and a donkey walking under The Tower of Justice, the original entrance gate…

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically as The Tower), is a historic monument in central London, England, on the north bank of the River Thames. The Tower of London is often identified with the White Tower, the original stark square fortress built by William the Conqueror in 1078. However, the tower as a whole is a complex of several buildings set within two concentric rings of defensive walls and a moat. The tower's primary function was a fortress, a royal palace, and a prison (particularly for high status and royal prisoners).

Procession to the Tower of London

Her Majesty's Royal Palace and Fortress, more commonly known as the Tower of London (and historically…

The name Traitors' Gate has been used since the early seventeenth century, prisoners were brought by barge along the Thames, passing under London Bridge, where the heads of recently executed prisoners were displayed on pikes. Anne Boleyn, Sir Thomas More, Queen Catherine Howard, and Anne Boleyn's daughter, Elizabeth I, all entered the Tower by Traitors' Gate.

Traitor's Gate, Tower of London

The name Traitors' Gate has been used since the early seventeenth century, prisoners were brought by…