Mysterious stone sphere discovered in Bosnia

A huge stone sphere discovered in a forest near the town of Zavidovici, in Bosnia and Herzegovina, has led Bosnian archaeologists to speculate that it may be the largest and oldest sphere of its kind in Europe.

The sphere measures around 10ft in diameter and weighs around 35 tonnes.

The origin of the stone is unknown - but it is possible that it could date back to an ancient civilisation from more than 1,500 years ago.

See also: Ten unexplained archaeological discoveries

It has an eerie resemblance to the famous stone balls of Costa Rica.

However, some geologists believe it could be a natural phenomenon.