Every year in late spring or early summer Tisza River becomes the main attraction in the country. The area around Hortobágy National Park (Hortobágyi Nemzeti Park) is famous for its unique 'blooming' that actually has nothing to do with flowers. Millions of Palingenia longicauda, the largest mayflies in Europe, burst from the river to mate, which from some distance may seem like some kind of a blooming cloud.
Most of their lives, mayflies spend as larvae in large colonies on the riverbed. When they are mature, they suddenly emerge from the water. The time for reproduction is quite limited, only about three hours, after which they die. The Blooming of the Tisza usually lasts just for three to four days, during which the whole area around the river is covered in huge clouds of mayflies.