The celesta, which looks like a tiny piano but sounds like bells, was kept a 'state secret' by Tchaikovsky. After discovering it in Paris, he wrote to his publisher to buy one immediately but warned him not to tell other composers. He wanted the 'heavenly' sound to be a complete surprise for the premiere of 'The Nutcracker.' He specifically used its unique timbre to characterize the 'Dance of the Sugar Plum Fairy,' marking the instrument's first major orchestral success.