Two Long-tailed mayflies (Palingenia longicauda) are seen on the river Tisza in Tiszakurt, a village in Jasz-Nagykun-Szolnok County, central Hungary, on June 16, 2017. Millions of the short-lived mayflies engage in a frantic rush to mate before they perish in just a few hours during Tisza blooming season from late spring to early summer every year. Larvae of the species live in small holes in the river banks for three years before they develop into the final form of the insect to participate in the swarming and then die. (Xinhua/Attila Volgyi/IANS)