The subject of this article is Baltic summer solstice rituals. The main objective is based on the idea of syncretism at the mythological and ethnological levels, which has not been explored by researchers to date, i.e. the cosmogonic myth about the brother and sister, the Sun and the Moon, on the summer solstice and necroculture, the period when the remains of the dead are buried, with the main goal of establishing a connection between the transcendence of ghosts. Based on typological and analytical descriptive, and areal linguistic methods, the origin of the Baltic summer solstice feast is hypothetically linked to the emphasis on the temporary contact between different worlds (the living and the dead) during the summer solstice, which determines the order of the world, vegetation, and a good harvest.