OEA
The last of the three cities of the Tripolis (From which Tripoli gets its name) is Oea. Unlike the other two Roman cities which are somewhat remote, and therefore mostly recognizable, Oea was built in the center of what is now the Medina of Tripoli. Founded by the Phoenicians about 500 BC, Oea flourished under Roman rule until around 200 AD. It was pretty well destroyed by the time the Vandals invaded in the forth century AD. The Medina was built using the using the rock, marble and columns of Oea. Other than the Arch of Marcus Aurelius there is little readily visible to show that a significant Roman city existed here. Little, until you start looking closely...
The Arch of Marcus Aurelius still stands at what was the major crossroads of the ancient city. A few broken columns and building parts are scattered around.
The Arch isn't readily visible from the main roads, and has little tourist traffic.
It makes a spectacular backdrop to several very good restaurants.
So, what happened to the rest of the Roman ruins? I searched all through the Medina, and finally found the answer.
The stone was used to build the buildings of the Medina and are mostly covered by plaster. In some cases columns were left exposed like at this portal.
The columns started popping up all over the place. Here in the gold souq plaza the columns supporting both levels are Roman.
The mosques used many columns in their construction.
Even the local hooka joint (water pipe smoking venue) used them for two levels. I'm still looking for more...
And when I need to take a break from the search, I come to my favorite table at the Andalusia Restaurant and watch the world spin over a Beck's non-alcoholic beer...