George S.
Google
Corinth was a superpower not only of the ancient Greek world, but the ancient world altogether.
Its origins are lost deep within the Neolithic age, alas little remains of this era as well as the ones following it (i.e. Mycenean) as it was constantly inhabited and these were covered by multiple layers of overstructures.
The wealthiest city in the Greek world produced the Corinthian helmet, the iconic, practical and economically produced helmet that protected most Greek hoplites for centuries.
It also designed and produced the trireme, the legendary warship that dominated the seas and won battles such as Salamis and Mykali.
Its colonies were multiple, and some became renowned cities in their own right, such as Syracuse and Epidamnos (which today we know as Dyrrhahium or Durres, as renamed).
Its greatest period was during the Archaic age, under the guidance of Periandros. The core of all that can be seen here was built in those times.
The ascension of Athens as the premier sea power and the loss of Corinthian seafaring profits triggered the Peloponnesian war. The Corinthians were cunning enough to manipulate Sparta into fighting for their interests, masterfully leveraging Spartan pride.
The bill came very much later, in 146 BC, when it was mercilessly sacked by the Romans, who a full century later financed its reconstruction.
The city enjoyed a second extensive period of prosperity that was disrupted by barbarian raids in the late 3rd and late 4th century AD.
Walk around and get a taste of these. It's easy to visit. Refreshments and food can be found right outside the gates.