What was the purpose of the Pharos lighthouse?

The main function of the Pharos lighthouse was to illuminate the way for ships heading to the bay of Alexandria. The light of the lighthouse, according to information from various sources, could be seen at a distance of 51 to 81 kilometers, and gave them the opportunity to safely pass the reefs on the way to the bay. Due to its size (up to 135 meters), the lighthouse was recognized as one of the seven wonders of the world. After the bay of Alexandria lost its significance, the lighthouse fell into decay, and later (in the XIV century), it was destroyed as a result of a strong earthquake.