The owners make several claims: 1) Their restaurant is the oldest in the neighborhood. 2) They invented flaming saganaki in 1968, and it has since been exported to Greece, and 3) Parthenon was the place that brought gyros to Chicago. What we know for sure: There are more than 140 dishes offered, including sea bass, red snapper, calamari, moussaka and vegetarian preparations. Portions are huge. You can even order a whole roasted suckling pig (feeds 12; call ahead) and lamb's head. The floors in the cocktail lounge feature green Greek marble; the dining room seats 300 and can accommodate private parties.