A man holds a long-tailed mayfly (Palingenia longicauda) in the Tisza river near Tiszainoka
A man holds a long-tailed mayfly (Palingenia longicauda) in the Tisza river near Tiszainoka, Hungary, June 16, 2017. Millions of these short-lived mayflies engage in a frantic rush to mate and reproduce before they perish in just a few hours during "Tiszaviragzas" or Tisza blooming season from late spring to early summer every year. REUTERS/Laszlo Balogh