The Tjängvide image stone dating to the Viking Age found in Gotland, Sweden and probably showing Odin on his horse Sleipnir (or otherwise a dead man arriving at Odin's hall of Valhalla) on the middle-right.
Based on Wikipedia content that has been reviewed, edited, and republished.
Original image by Berig. Uploaded by Emma Groeneveld, published on 10 November 2017 under the following license: GNU Free Documentation License. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.