For thousands of years, the people of Mesopotamia believed the gates into and out of heaven lay at opposite ends of the great curve of the Milky Way, called the River of Souls. After death, souls had to wait for the rising doorway of Sagittarius and the autumn equinox, when day and night are equal. Reincarnation back to Earth could only take place during the spring equinox through the Gemini exit in their night sky.