Tyre (Phoenician רצ, ṣūr, "rock"; Greek Τύρος; Latin Tyrus): port in Phoenicia and one of the main cities in the eastern Mediterranean.
The octagonal building can be found in the northern part of Tyre's city excavations. The building itself is not very large, but surrounded by magnificent colonnades. In the southwestern colonnade is a small building. Part of the decoration looks Egyptian.
I have not been able to discover more about this monument, which was easily one of the largest and splendid in the neighborhood. Likewise, I was unable to find out what the small inner structure was: did it belong to the original monument or is it a later, perhaps Byzantine addition?