The famous “Duck” at the Avenida Palace Hotel in Barcelona. The famous “Duck” at El Avenida Palace in Barcelona is an optical illusion created by the hotel’s e

The famous “Duck” at the Avenida Palace Hotel in Barcelona. The famous “Duck” at El Avenida Palace in Barcelona is an optical illusion created by the hotel’s elegant spiral staircase. Viewed from the very bottom while looking straight up, the staircase’s sweeping curves, brass railings, and geometr…