Inca complex at Pisac, Peru

Portchester Castle, England, in the mid-14th century AD

Overgrown remains of Alvarado Tower, Secadura, Spain

Reconstruction of an early medieval European fortified settlement (Giorgio Albertini)

Tower of Gunib Fortress, Republic of Dagestan

Remains of Alamut Castle, Iran

Italian fortified village of the 10th century AD (Giorgio Albertini)

Imagining of Norwich, England, in the 14th century AD

Byzantine ruins near Chaouach, Tunisia

Cutaway of a medieval tower house