Beltane

From Wikipedia:

Beltane (/ˈbɛl.teɪn/) is the Gaelic May Day festival. It is held on 1 May, or about halfway between the spring equinox and summer solstice. Historically, it was widely observed throughout Ireland, Scotland, and the Isle of Man. In Irish the name for the festival day is Lá Bealtaine ([l̪ˠaː ˈbʲal̪ˠt̪ˠənʲə]), in Scottish Gaelic Latha Bealltainn ([l̪ˠaː ˈpjaul̪ˠt̪ɪɲ]) and in Manx Gaelic Laa Boaltinn/Boaldyn. It is one of the four Gaelic seasonal festivals—along with Samhain, Imbolc and Lughnasadh—and is similar to the Welsh Calan Mai.

Apparently they've been doing a fire festival in Edinburgh since 1988. The BBC has pictures from this year's seasonal fest.