This is Corinth. These ruins were once the great ancient city of Corinth. Paul wrote the Corinthian letter to the church of new Christians there. Wow. That grate is covering a spring cistern. Once there was a giant, round-ish stone covering the cistern.
This is my Greece | The Corinth Canal is a canal that connects the Gulf of Corinth with the Saronic Gulf in the Aegean Sea. It was completed in 1893.