What did the Pharos lighthouse look like? What purposes did it serve?

What did the Pharos lighthouse look like? What purposes did it serve? Why did the Greeks call it one of the wonders of the world?

The Pharos or Alexandria lighthouse was a quadrangular tower, the height of which exceeded 120 meters, and the sides of which were strictly oriented to the cardinal points. The lighthouse was crowned with a lantern and a statue of Poseidon, whose height was 7 meters. The lighthouse not only showed the way to Alexandria. Its light beam, created with the help of metal mirrors, made it possible to observe the sea at night and prevent enemy ships from sailing unnoticed. The lighthouse was also a fortress. And it is considered a wonder of the world because it was one of the tallest structures of its time.