The Beryozka dance is a dance developed in the Soviet Union in the 20th century. It's now reached the status of beloved tradition because of the way the women's costumes and small dance steps make them appear to glide across the stage.
The glide dance is also sometimes transliterated as Berezka. Via Oil of Russia:
The dance was choreographed by Nadezhda Nadezhdina (1908-1979), the founder and constant director of the ensemble right up until 1979. From 1925 to 1934, she was a solo ballerina with the Bolshoi Ballet in Moscow. After beginning work as a teacher and choreographer in the mid-1930s, Nadezhda Nadezhdina in time came to stage original dance compositions on Russian folklore and folk art themes.
Initially, the Beryozka ensemble's repertoire was limited to just a few dances ("Girl's Dance", "Northern Round Dance", "The Swan", "The Chain", and "Snowstorm"), but each of them was carefully thought out, tried, tested and impressive. With its dances, the ensemble heralded the birth of a new style of performance in Russian theatrical choreography. That was when the famous round-dance-pictures appeared and when the amazing "floating" step, which to this day astounds audiences throughout the world, was perfected.
In 1949, at the World Youth and Student Festival in Budapest, the ensemble took first prize and the winner's laurels in the folk dance competition. In 1950, the Beryozka dance ensemble was awarded the State Prize of the USSR.
Here's vintage footage of the dance from a 1964 Soviet broadcast:
And here's a gorgeous update to the tradition using LED lighting: