During the 90’s, archaeologists uncovered the remains of the crusader castle of Beirut, as well as a crusader defensive tower, built on top of earlier defensive structures that dates back to the Roman era.
On top of the fort itself, few Ottoman remains were also discovered.
One can see rounded stones (which are Roman columns) integrated within the defensive walls of the tower. This was a construction method proper to the crusaders, it made defensive walls stronger.
The caste, along with the tower and defensive walls were heavily damaged in 1840 due to bombardments of the British naval fleet. It was raised to the ground in the late 19th century and all that remains of that castle is this fragment of a wall in DT Beirut