Fourteen thieves have been sent to prison for stealing items made from rhino horns and elephant tusks.
The criminal gang had stolen expensive items worth up to £57 million from different museums in the UK.
Rhino horns and elephant tusks are worth a lot of money, but it's against the law to buy or sell them.
That's because the animals are often illegally killed to get their horns and tusks.
Police think that the thieves had planned to sell the stole items in China, where there's a big demand for them because some people there believe they can be used in medicine.