Aerial photo taken on June 30, 2018 shows a general view of Color Day Festival at Athens Olympic Stadium, Athens, Greece. (Xinhua/Lefteris Partsalis)

Greek famous pop singer Sakis Rouvas performs during Color Day Festival at Athens Olympic Stadium, Athens, Greece, June 30, 2018. (Xinhua/Lefteris Partsalis)

People play with colored flour during Color Day Festival at Athens Olympic Stadium, Athens, Greece, June 30, 2018. (Xinhua/Lefteris Partsalis)

Kids play with colored flour during Color Day Festival at Athens Olympic Stadium, Athens, Greece, June 30, 2018. (Xinhua/Lefteris Partsalis)

People play with colored flour during Color Day Festival at Athens Olympic Stadium, Athens, Greece, June 30, 2018. (Xinhua/Lefteris Partsalis)