The swarming of mayflies is a mystery, an excitement, an indescribable magic. This rare, once-in-a-year phenomenon lasts for only one or two weeks, the insects from the underwater larvae of mayflies perform their spectacular nuptial dance above the water, just to die within a few hours. It is magic, a unique European experience on the River Tisza. In Szolnok, the nuptial dance of mayflies can be enjoyed on the River Tisza from the middle until the end of June.