Samhain is the name for traditional Halloween festivities in Ireland. It is an ancient Celtic festival that was celebrated on the night of October 31st to mark the end of the harvest season and the beginning of winter. Samhain was a time when the boundary between the worlds of the living and the dead was believed to be the thinnest, and people made offerings to the spirits and ancestors. Today, the celebration of Samhain is still an important part of Irish culture, and Halloween is recognized as a national holiday.