Midsummer, the period around the June solstice, has been marked with celebration across a wide range of northern cultures, most prominently in Scandinavia, where Midsummer's Eve remains one of the most widely observed holidays of the year in Sweden, Finland, and Norway, marked by maypole raising despite the summer rather than May timing of the term, bonfires, flower crowns, and outdoor feasting that make the most of the extremely long daylight hours at that latitude.
St John's Eve, falling close to the solstice on the church calendar's observance of the birth of John the Baptist, absorbed many pre-existing midsummer bonfire and water blessing customs across much of Christian Europe, a pattern in which an existing seasonal observance and a fixed point on the liturgical calendar came to sit close enough together that folk practice often blended the two without much concern for which element belonged to which origin.
Modern Wiccan and broader neopagan practice marks the solstice as Litha, one of the eight sabbats of the Wheel of the Year, generally themed around the sun's peak strength and, since the solstice also marks the year's turn back toward shortening days, around the idea of abundance reached at a cost, the point after which the balance the year holds begins tipping the other way.