Photo taken on Aug. 4, 2017 shows the entrance to the Athens National Observatory amid trees and plants on the Hill of the Nymphs in the centre of Athens, Greece. Celebrated Argentinean artist Adrian Villar Rojas has transformed this summer the outdoor space of the Athens National Observatory opposite to the Athens Acropolis into a "jungle", posing to locals and foreign tourists questions regarding disappearance, extinction, the passage and volatility of time. (Xinhua/Lefteris Partsalis)
