The walls of the medieval city of Barcelona are still visible from the streets.
The walls were designed to shield the city from attacks by the Spanish king, but they were also used as a defence against the Muslim invaders of the 13th century.
Madrid, with a population of 5 million, was one of the largest cities in the Spanish empire, and its walls served as a barrier against the invading Spanish army.
The walls of Barcelona were built in the 1380s, and it was believed that they were the first major walls in the world.
As time passed, the city wall began to crumble and the walls were replaced with smaller, more porous ones.
By the time the city was sacked by the Ottoman Turks in 1453, the walls had fallen to ruin, and by the 1520s, the area was known as Madrid.
Since the collapse of the walls, Madrid has been covered in graffiti, and the area around the walls has been largely deserted.
According to the UNESCO World Heritage website, the Madrileño walls have been covered with graffiti to warn of the threat of attack.
While it is believed that the walls are still standing, some of the graffiti still reads: “Madrid Walls”.
This article originally appeared on The Times Of India