I really enjoyed my visit to this WHS, way more than I was expecting.  Having seen both Roman ruins and Mosaics elsewhere, I wasn't expecting to be impressed.

However, the huge Roman Mosaic covering almost the entire floor of the Basilica is one of the most breathtaking that I have ever seen.  Both its scale and content are impressive, I particularly enjoyed the fishing scenes.

Also in the Basilica are two crypts, one of Frescos, one of Excavations. I visited only the former and again, found the frescos to be better than I imagined.  The colours are vivid and the emotions depicted on the subjects faces are incredible.

The cost for the Basilica and Crypt of Frescos is EUR 5, an additional couple of Euros buys you entrance to the Crypt of Excavations and another 2 euros for the climb to the bell tower.

Wandering around the additional roman ruins (for free) is a low-key event but enjoyable nevertheless, especially the warehouse and port ruins, which I haven't seen much of previously.