The ruins of Delphi were uncovered by the systematic excavations of the French Archaeological School, which began in 1893. The village of Kastri, which had occupied the area of the sanctuary since medieval times, was moved to its present position. After the removal of huge quantities of earth that had been accumulated with the landslides, the remains of two sanctuaries, dedicated to Apollo and Athena Pronaea, were finally uncovered. The excavations revealed more than five thousands inscriptions of all kinds, statues, several miniature objects, architectural decorative pieces, all exquisite works of art, representing the major cities of Greek antiquity. Outside the area of the Sanctuary, the Stadium, the Gymnasium, the settlement of Delphi and its cemeteries have also been excavated.

The only monument that could be fully reconstructed from its own building material was the Treasury of the Athenians, which was restored in 1903-1906 by the French excavators, at the expense of the Municipality of Athens. In 1959, the restoration of the altar of the Chians was completed by the Greek Archaeological Service. The gradual reconstruction of parts of the Tholos and the Apollo Temple since 1938, has resulted in major changes in the overall appearance of the ancient remains; the Tholos has been rebuilt up to the marble sima at the base of the roof, while of the Temple have been restored the north crepis, the north wall, the columns on the east side, and the ramp of the entrance.