Pharos Lighthouse of Alexandria

This Lighthouse of Alexandria was considered the 7th Wonder of the ancient world

Construction

Started by Ptolemy I Soter who died prior to its completion

Enormous cost and slave labor were employed

The architect was Sostrato the Greek

Completed and inaugurated by the first Ptolemy's son, Ptolemy II Philadelphus, in 283 BC.

The lighthouse was reached from Alexandria's harbor through an approach that extended 3.5km and connected the city with Pharos Island.
it consisted of a monumental edifice with three tiers, consisting of a lower quadrangular one, surmounted by an octagonal layer and topped by a cylindrical section. The approach to its entrance was by way of a long ramp with vaulted arcades. Within, a large spiral ramp led to some fifty service rooms in the third tier were wood was used to burn a fire that acted as the light source, which could be seen from almost 100 miles out to sea

Features
the lowest square, measured about 55.9 m high with a cylindrical core
the middle octagonal with a side length of 18.30 m and a height of 27.45 m
the third circular 7.30 m high.
The total height of the building including the foundation base was about 117 m

Destruction
In 796 the lighthouse lost its upper tier, and went without repair for about a century.
In 950 parts of its surface cracked and to stabilize it, the lighthouse was reduced by some 22 meters in height.
In 1303 a major earthquake shook the whole eastern Mediterranean and the Pharos was destroyed
This was to be the end of the 7th Wonder of the ancient world,