The "hogueras de San Juan" is a tradition of pagan origin celebrated in Spain in the night of June the 23rd, precisely the beginning of the summer solstice.

This tradition is celebrated all across Spain, in every city but mostly in beaches, and consists of people burn all sorts of old furniture. But this celebration would be nothing without the firecrackers that bang all night, something little children love doing!.

However, San Juan tradition is lived in many different ways all across Spain: every region and city might have their own particular ritual or particular celebration but i will answer this more thoroughly in another Qsponge question!.