Theatre safety curtains have frequently been embellished by artists and set designers—a way of enlivening an inherently bland and practical feature in an otherwise grand, decorative setting. But the Vienna State Opera has taken this concept a step further, transforming its curtain into an ongoing exhibition series, titled Safety Curtain. Every year since 1998, the opera house has invited an acclaimed artist to co-op the fire-proof sheath as a canvas for their own site-specific work. Kara Walker, Maria Lassnig, Franz West, David Hockney and many more have been involved in the project. As has Cy Twombly, creator of this quintessentially squiggly piece, installed between 2010 and 2011, the year of the American artist’s death.