The luxury retreat Golden Door introduced the Circle, a 360-degree open-air immersive stage, last August on its 600-acre resort near San Diego. The Circle pairs surround-sound live musical performances with art projections to produce rejuvenating results. “It was relaxing and meditative, the stars above, immersive visuals and the cello harmonizing with nature’s own night music,” said Bradford Bricken, 45, from Memphis, who was a guest in September.