Panathinaiko or Panathenaic Stadium (Greek: Παναθηναϊκό στάδιο), also known as the Kallimarmaro (Καλλιμάρμαρο, i.e. the "beautifully marbled") in Athens is the only major stadium in the world built entirely of white marble (from Mount Penteli). It should not be confused with the Panathinaikos football pitch (officially called the Apostolos Nikolaidis stadium) at Alexandras Avenue.
In ancient times it was used to host the athletic portion of the Panathenaic Games in honour of the Goddess Athena. During classical times the stadium had wooden seating. It was remade in marble by the archon Lycurgus in 329 BC and was enlarged and renovated by Herodes Atticus in 140 AD, to a seated capacity of 50,000. The remnants of the ancient structure were excavated and refurbished, with funds provided by Evangelis Zappas for the revival of the Olympic Games. Evangelis Zappas sponsored the Olympic Games that were held there in 1870 and 1875. The stadium was refurbished a second time in 1895 for the 1896 Olympics, with completion funding provided by the Greek benefactor George Averoff (whose marble statue now stands at the entrance), based on designs by architects Anastasios Metaxas and Ernst Ziller.