Where did Baltic traditions place the invisible world visited by the sun at night?

In Baltic traditions, the invisible world visited by the sun at night is known as viņa saule (literally "the other sun"). This realm is also considered the abode of the dead.1

Regarding its specific location, the evidence remains inconclusive. Baltic folklore does not definitively state whether this world is situated in the direction of the setting sun or located under the earth, beneath which the sun travels to return to the east. Some traditions suggest the sun makes her way from west to east under the earth to begin her journey anew over the sky mountain. Additionally, there is a possibility that this concept is linked to the ancient idea of a world ocean upon which the earth floats as a round plate.1