Photo taken on May 21, 2018 shows a Pelophylax Kurtmuelleri frog on the shores of an artificial lake near the town of Thessaloniki, Greece. The United Nations has proclaimed May 22 the International Day for Biological Diversity to increase understanding and awareness of biodiversity issues. (Photos: Xinhua)

Photo taken on May 22, 2018 shows a pair of Pelecanus Crispus flying above lake Mikri Volvi near the town of Thessaloniki, Greece. The United Nations has proclaimed May 22 the International Day for Biological Diversity to increase understanding and awareness of biodiversity issues.

Photo taken on May 22, 2018 shows a group of Pelecanus Crispus on lake Mikri Volvi near the town of thessaloniki, Greece. The United Nations has proclaimed May 22 the International Day for Biological Diversity to increase understanding and awareness of biodiversity issues.