Beneath each full moon on the outskirts of a village in central Mexico, a group of women in nun habits circle a roaring fire, cleanse themselves with burned sage, and give thanks for the moon, animals and plants.

Then they inhale deeply from a joint and blow clouds of marijuana into the flames.

Despite their clothing, the women are not Catholic or any other religion. They are part of an international group founded in 2014 called Sisters of the Valley, which has pledged to spread the gospel of the healing powers of cannabis.