When you lose a tooth, do you put it under your pillow and wait for the tooth fairy to call?
An artist in Liverpool had a very different idea and decided to create a sculpture decorated with real teeth.
It's been named the Tooth Fairy's Palace and has a frame made of clear resin into which teeth are carefully glued.
The piece is being built to raise awareness about stem cell research and what it means to science.
Stem cells are a type of cell that can be encouraged to develop and grow into any part of the body. Scientists think that ability could make them very useful in treating diseases in the future.
Teeth contain these special cells.
The artist, Gina Czarnecki, is relying on children donating their baby teeth in exchange for a token to place under their pillows for the tooth fairy.
The sculpture will gradually become covered in teeth and will be on display at Liverpool's Bluecoat Museum, before moving to the Science Museum in London next year.