The Festival of Ivana Kupala
Image taken from the Ukrainian Catholic Church in Koln website
On the eve of the 6th of July , Ukrainians celebrate the Festival of Ivana Kupala. This is an old pagan ritual that goes back to the time of the people who lived in Rus' (ancestors of current Ukrainians). Then the Festival was celebrated on Midsummer night's eve.
After Ukraine (called Rus' - at the time) became a Christian country in 988, this pagan Festival was Christianised and was then linked to the birth of John the Baptist.
During the Festival, single ladies make head wreaths from flowers and float them down a river; their true love then picks up the wreath from the river. In addition, a bonfire is built and the men jump over it.
Participants make straw effigies of Morena - the pagan god who represents water and Kupala - who represents the sun. Morena and Kupala "meet" and "get married". At the end of the Festival, Morena is thrown in the river and Kupala is burnt in the bonfire.
The most unusual tradition is the search for the flowering fern which legend has it, only flowers this very evening. The flower has magical properties - the finder will be able to understand the languages of animals and plants.
https://www.encyclopediaofukraine.com/display.asp?linkpath=pages%5CK%5CU%5CKupalofestival.htm
https://www.rferl.org/a/ivan-kupala-night-ukraine/31320288.html