In the Irish ritual year Bealtaine and Samhain have many similarities, both being times when the 'veil' between the Otherworld and the human realm becomes thin. Bealtaine is more connected with the sidhe (fairies) and Samhain with the dead (but with fairies too). Both are connected with divination and with magic (or the perceived threat of magical interference in people's lives). I've always found the fact that the two festivals are on the same axis on the Wheel of the Year to be very interesting. I was just talking about this with a class today!