This odium (a smaller version of an amphitheatre) is part of the ruins excavated at the ancient city of Troy (Troia or Troya), located near Canakkale in Turkey.
Troy has multiple 'layers' of ancient cities, dating back to 3,000 BC, with this odium being in the relativelly recent ancient Roman ruins.
Canakkale was a great surprise for me. I expected it to be a logistics stop, and a stepping off point for a battlefields visit to Gallipoli, but found it to be so much more.
Apart from Troy, the Gallipoli visit was brilliant, and sobering, and the city of Canakkale was a pleasant place to wander around and explore.
Canakkale was also interesting in that it straddles two continents, with the main township on Asia, while just across the Dardanelles lies the European side of the city.