13 outrageous items sold by auction houses Christie's and Sotheby's

There's more to auctions than grand paintings and neo-modern furniture.

Auction sales around the world grew by 25% in 2017 - with help from da Vinci's "Salvator Mundi," the most expensive piece of art ever sold - according to ArtTactic. Two of the largest auction houses, Christie's and Sotheby's, are known for their classic repertoire - but both have sold surprising items at auction.

For example, in September 2013, somebody purchased a Triceratops' skull for over $270,000. At 75 inches long and 88 inches high, the artifact found in Montana is one of the oldest pieces sold by Christie's.

Aside from ancient dinosaur bones, these auction houses have seen other strange purchases for large bids. Take a look at 12 more odd items sold at auction.