From the supposed tomb of King Arthur to ancient Egyptian temples once controlled by female priests, the world's religious sites are home to alluring secrets and mysteries. This summer, Smithsonian Channel brings back SACRED SITES to explore even more enigmatic religious sites found around the world. Featuring advanced scientific discoveries and archaeological research, new episodes will bring viewers to sanctified and historical locations stretching from Europe to North Africa, through the Mayan civilization in the Americas, across the path of the Camino de Santiago and more. SACRED SITES returns Monday, August 13 at 8 p.m. ET/PT on Smithsonian Channel.