I visited this WHS in June 2014. It's one of the most crowded sites in Greece. However, most tour groups gather mainly in the shade of the trees near the Temple of Apollo and in the archaeological museum of Delphi, afraid of the scorching sun. Most don't even visit the theare and the stadium that are high above the Temple of Apollo. These were my personal favourites as they offer great views of the surrounding mountains and a great panoramic view of the Archaeological Site of Delphi. About 250 metres away, I visited the Ancient Gymnasium and the Athena Pronaia Sanctuary which has the famous tholos (picture). All in all a great classical site but not the best Greece has to offer.