At night on Aug. 16 every year, five characters or shapes of fire are lighted on five mountains surrounding Kyoto city.
The souls of ancestors are believed to come back to the earth in every August and to return to heaven on 16th of the month. The fire lighting called "Daimonji" is a religious event to see them off.
The meaning of the lighting chinese character "Dai"of the above photo is "great". These too big characters of fire are very beautiful and mysterious.

Chinese character "Dai"