Mithras stela (early 3rd century AD) excavated in Heisterbacherhofstrasse in Bonn, now in the Rheinisches Landesmuseum in Bonn, Germany. Behind the crescent-shaped opening is a space for a lamp in order to create light effects, characteristic for the Mithras cult. The relief depicts a grazing cow, a snake and a vine (largely erased).
<a href="//commons.wikimedia.org/wiki/User:Kleon3" title="User:Kleon3">Kleon3</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>