That's a merry-go-round that is hiding inside this Imperial Egg. And yes, it is a working merry-go-round -- ingenious! Clicking on this site will enable you to see many of the 'Imperial Eggs' their hidden treasures.
The Winter Egg, considered by experts to be the most beautiful of all of the Faberge Eggs and the most expensive one. It was created by Alma Pihl, the only woman-master of The House of Faberge in 1913 for Maria Feodorovna, the mother of Nikolay II.