It is a naked-eye observatory built in the cinder cone of a volcano. A place very far from light pollution where you can stand in a comfortable place and look up to behold the heavens. James Turell's pieces are all about the feeling of being in an "other" sort of plane, so you can expect a lot of trippy rooms inside the facility that will make you question what it means to exist. Or that's what happened to me inside of one of his pieces, anyway.