A huge fossilized elephant bird egg was sold at auction in London for $101,813.

The elephant bird egg was originally valued at an estimated $30,500 to $45,750 pre-auction, but during the Christie’s “Travel, Science and Natural History” auction on Wednesday, it was sold to an anonymous buyer over the phone after about 10 minutes of competitive bidding.

James Hyslop from Christie’s Auction House said that the high price tag came from the fact that this is one of the only complete elephant bird eggs to exist. Hyslop said: “It’s the first one that I’ve handled that is absolutely complete. The only other examples I’ve seen were patched together from various pieces.”

The elephant bird egg measures 8.75 inches in diameter and was found in Madagascar. The Elephant Bird itself, could weigh up to 1,000 pounds and grew as tall as 10 feet, BBC reports.

Elephant birds were once common on the island of Madagascar up until the 17th century. French governor of Madagascar in the 1640s and 1650s, recorded frequent sightings of the elephant birds. Also, the explorer and traveler Marco Polo mentions very large birds in his journeys to the East during the 12th and 13th centuries.

“The elephant bird was thought to be the giant flying beast known as the Roc (or Ruhk) in the tales of Sinbad and accounts of Marco Polo’s voyages,” according to Christie’s lot notes. “The bird grew to around 10 or 11 feet in height and whilst probably unable to devour an elephant, as the Roc was reputed to do, it certainly was the largest bird ever to have lived.”

It’s believed that the elephant bird’s extinction resulted from human activity.

A very large and valuable elephant bird egg sold for more than $100,000 at a London auction.