Milagre

From Orson Scott Card Wiki

Because of the Descolada virus, Milagre was the only city on Lusitania, authorized by the Starways Congress so that xenobiologists could study the new sentient lifeform known as pequininos (but usually called "piggies.") Milagre was surrounded by a high wall that was meant to keep the "piggies" from discovering new technology from the human encampment.