Question: Which annual gathering that takes place at Black Rock City did Further Future want to change the  "vanish and leave no trace" principles instilled in those who participate in it 
Sentence (from "Burning Man"): The event is described as an experiment in community and art, influenced by 10 main principles: "radical" inclusion, self-reliance, and self-expression, as well as community cooperation, civic responsibility, gifting, decommodification, participation, immediacy, and leaving no trace.
Relevant evidence: No