Courtesy of a link at Dark Roasted Blend, I was surprised to find that a well-known British rock ballad from 1971 has become a folk tradition in Bulgaria. Wikipedia reports:
In Bulgaria, there is a tradition called July Morning which is believed to be an echo from the hippie era of the 1960–1980s. Although not universally observed in the country, it is unique as it is not observed anywhere else in the world.
Usually, in the days before 1st of July, people from across Bulgaria travel (often hitchhiking) to the Black Sea coast to meet the first sun rays on the first day of July. People gather around fires, play music and wait for the sunrise. There is no mandatory ritual, ceremony or rite for this tradition and it is up to participants' discretion how will they spend the night before July 1. On many locations, there are concerts with professional and amateur bands. Camping at the locations of choice for the July Morning celebration is also very popular.
. . .
The name of the tradition comes from the British rock band Uriah Heep's 1971 hit "July Morning" which became widely popular in Bulgaria in the 1980s and somehow named and remained central to this unique Bulgarian tradition.
There's more at the link.
I'm familiar with the music of Uriah Heep, having listened to it during my youth. Intrigued, I turned to YouTube: and, sure enough, there's a video of the song with visuals taken from Bulgaria's annual celebration. It's kinda fun to see the two 'superimposed' on each other, as it were.
Looks like a lot of people having a lot of fun. I'm sure Uriah Heep are pleased.