They flip, fly, and walk tightropes—then pack up, move on, and do it all over again. In Circus: Wandering City, the adventurous string quartet ETHEL pays tender tribute to the culture that sustained the “Greatest Show on Earth,” which took down its tent for good last year. Using the vast resources of the John and Mable Ringling Museum—including firsthand accounts from contemporary circus performers and archival imagery—the ensemble performs its original score, diving into an overlooked, long stigmatized, and largely immigrant American subculture, whose denizens overcame the odds to swing and soar.