Sacred sites are among the most visited and revered places in the world. They offer visitors and pilgrims extraordinary impressions, intense experiences that hint at a higher presence and open up higher levels of vibration and consciousness. The downside is often overcrowded sites full of tourists who ruin this privileged moment by their presence. "Secret Sacred Sites" gathers 100 lesser-known places of worship, whose existence is often only known to locals, and thus stands for an authentic visitor experience. ?For forty years, National Geographic photographer Martin Gray made pilgrimages around the world. From his travels to 160 countries, he brought back photographs of hundreds of such lesser-known sacred sites. In this selection, he presents us with his favourite places, the result of a lifelong search.