Devised in 1948 by Russian choreographer Nadezhda Nadezhdina, the “floating step” of the Beryozka Dance Ensemble seems to carry dancers smoothly across the stage, as though their feet have left the ground.

“Not even all our dancers can do it,” Nadezhdina said. “You have to move in very small steps on very low half-toe with the body held in a certain corresponding position.”