Lake Tana, in North-East Ethiopia, is a huge lake fed by dozens of small streams. Its waters escape down a series of falls to become the Blue Nile. The lake counts 37 islands and forty churches grace its banks, a unique setting for the priests from the ancient convent of Estifanos to withdraw from the world and defend themselves against Muslim invaders. The monks live off what they grow; their days are divided between prayer, meditation and working their land. No female being has ever set foot on it. “The flesh is weak, and we must keep ourselves from temptation." So no women on the island, and no hens, cows, or ewes either.