Beltane Festival is a Gaelic festival celebrated on the first day of May. In Wiki source it is said that Beltane (and other spellings like "Bealtaine") is simply the name of the month of May. Beltane marks the beginning of summer and celebrated usually with the bonfires on some open areas in the hills." The bonfires will mark purification and transition, heralding in the season in the hope of good harvest later in the year, and are accompanied with ritual acts to protect the people from any harm of Otherwordly spirits". Same could be down to a cattle which had to be lead between two bonfires in order to be purified (Wiki).
|Beltane (image credit: Hamish Burgess)|
I think that Beltane celebration is a beautiful tradition which I can connect to such Russian festival like Maslenitsa, which marks the beginning of spring.
Walpurgis Night is a traditional spring festival celebrated on 30th of April or 1st of May in Northern and Central Europe. The current festival got it's name after English missionary Walpurga canonized on the 1st of May. However this day became associated with May Day. This day is known as Walpurgisnacht (German and Dutch).
Walpurgis night was traditionally considered to be witches' "get together" - Sabbath. I remember I used to read that this night witches were believed to meet with devil. There were also lit bonfires, around which witches would dance and do rituals.