Bealtaine (pronounced Beeyaltineh) is the Celtic festivity that indicates the begining of the summer, it's hold in the middle between the spring equinox and the summer solstice, and even in modern Irish, the name of the month that we know as May is Bealtaine.
Is resembles the lights of Bilé, the sacred tree, the world tree who get togheter with Danna, in the form of the River Danube, as partners, they give life to The Dagda and the Tuatha dé Danna.
Bile also spelled Bel is a sun god, a fertility god; patron of cattle, since Bealtaine celebrates the fertility, as the beginning of the summer, and the growing season. The word "Bealtaine" literally means "bright" or "brilliant fire," and refers to the bonfire lit by a presiding Druid in honor of Bile.
The festival is hold in the eve of may 1, as known the day for the Celts begin at the sunset. This is a time of fertility, blossoming, creativity, union.
May it light your lifes!