Hadrian's Arch, Athens — erected around 131 AD to mark the boundary between the old Greek city and the new Roman quarter Hadrian built for himself. Its dual inscription — 'This is Athens, the city of Theseus' on one face, 'This is the city of Hadrian, not of Theseus' on the other — is the most concise summary of ancient Athens's complicated legacy ever carved in stone.
© Carole Raddato from FRANKFURT, Germany, CC BY-SA 2.0, via Wikimedia Commons