CIMRM Supplement - Mithraeum. Thermes, Greece.
At Kato Thermes in Greece, there is a very weathered relief of Mithras killing the bull in a rock-cliff. It was originally discovered in 1915.
From: Archaeology Magazine:
According to Greek Wikipedia, the relief shows Mithras killing the bull between Cautes and Cautopates. Under the bull, the snake can be made out, and on one side another form, which might be Sol or Luna. At the bottom are a series of frames from the cycle of the god,. The relief dates to the 2-3rd century. The information is referenced to archaeologists Marie-Gabrielle Parisaki and Louisa Loukopoulou.
An article online states 1 that the relief is 6km from the Bulgarian border and is accessible using the Zlatograd customs crossing.
Dr Szabo Csaba adds, in his list of new finds: "Interestingly, Bulgarian archaeologist Nikolay Ovcharov identified the veneration of rocks as a cultic ritual that was part of this Mithraic complex, resonating with the story of Mithras's rock birth."