Under the direction of E. Hector Williams (University of British Columbia) the Stymphalos project ran from 1994-2012 and excavated 15 different areas of the city of Stymphalos. Significant discoveries include the fact that part of the city was abandoned and then resettled, while in another area, a large Hellenistic stage building to go with the rock cut seats on the eastern end of the acropolis was found. Evidence for Bronze age settlement was also found (though the site primarily dates to the Classical, Hellenistic, and Early Byzantine periods), as was a sanctuary, likely to Athena, full of pottery, lamps, terracotta figurines, and large quantities of gold, silver and especially bronze jewelry and destroyed in the mid-2nd century BCE. Elsewhere in the city, gates, sections of the city wall, artillery towers, remains of over 100 iron ballista points, and several more early Christian burial sites were uncovered. In the valley surrounding the city of Stymphalos, elements of at least five major Doric buildings have been recovered, suggesting considerable wealth and an ambitious building programme during the 5th and 4th centuries BCE.
More on the project can be found here: http://portal.cig-icg.gr/node/111