The Derdap National Park preserves part of a feature with this name, where many historic sites were submerged by two  ►  Ceausescu-era hydroelectric dams.
This is an alternate name for the pass of Biban in central Algeria, where Marshal Valee's movement of a French army in 1839 caused the breakdown of the Treaty of Tafna.  This name was also used for what Chinese sources call the Tiemenguan, a passage on the road to Samarkand that supposedly kept the Western Turks from invading the land of the Tokharians. A third feature with this name include the now-submerged Turkish smuggler island of Ada Kaleh and the Mesolithic village site of (*) Lepenski Vir. The Derdap National Park preserves part of a feature with this name, where many historic sites were submerged by two  ►  Ceausescu-era hydroelectric dams. For 10 points, give this name shared by a gorge of the River Danube on the border between Serbia and Romania.
This is an alternate name for the pass of Biban in central Algeria, where Marshal Valee's movement of a French army in 1839 caused the breakdown of the Treaty of Tafna.  
Iron Gate (or Iron Gates or Gates of Iron)