Participants of the XXII World congress of Philosophy attend a concert at the ancient Roman-era Herod Atticus Theater, situated below the Acropolis, marking the congress’ official opening on August 4, 2013. Greece, widely considered as the birthplace of western philosophy, welcomes the 23rd World Congress of Philosophy, organised by the International Federation of Philosophical Societies (FISP), which opened in Athens today. TOPSHOTS/AFP PHOTO/LOUISA GOULIAMAKI