Bab Zuwayla, Cairo
This imposing gateway once formed the southern entrance to the Fatimid city of al-Qahira (Cairo) when it was founded in AD 969. The stone building dates to 1092 while the minarets (which are actually part of the adjoining mosque of al-Mu’ayyad Shaykh) were added later in the 15th century. The platform between thee two towers was used by Mamluk sultans to watch the beginning of the procession of the mahmal as it accompanied the annual pilgrimage to Mecca.
More gruesome perhaps, the gate was used for public executions and heads of criminals were displayed on spikes above the gateway.
Between 1998 and 2003 the American Research Center in Egypt conserved and restored Bab Zuwayla including its impressive wood and iron doors. Read about their project here.