1) Extensive ruins 
Acrocorinth (Ακροκόρινθος), `Upper Corinth`, the acropolis of ancient Corinth, is a monolithic rock overseeing the ancient city of Corinth, Greece. `It is the most impressive of the acropoleis of mainland Greece,` in the estimation of George Forrest. Acrocorinth was continuously occupied from archaic times to the early 19th century...
the citadel of ancient Corinth: strategic in the control of the Isthmus of Corinth; extensive ruins.