The capital city of Algeria is located on the Mediterranean coast, set against forested mountains and overlooking a bay. The modern city of Algiers is formed of two parts. The lower part is the French-built new town with wide boulevards, and all the cultural trappings of colonialism like an opera house, cathedrals, theatres, museums. The Casbah or old city forms the upper part of Algiers, replete with labyrinthine passageways and a 16th century walled fortress.