This one is interesting.
Not far from here, there’s a river with an interesting phenomenon, which is ‘the blooming of the Tisza’ (Or Tiszavirágzás in Hungarian). Basically, mayfly larvae are living in the riverbed for up to 3 years, then suddenly when the temperature of the water and air is right, they erupt from the water and cloud the air with literal millions of their number. They don’t last long in this form, a few hours tops. They mate and then die. Is this beautiful or sad? You decide. Here are some pictures.
