The world's oldest eye has been found in a 530 million year old fossil.
The remains of an extinct sea creature include an early form of the eye seen in many modern day animals including crabs, bees and dragonflies, researchers believe.
Scientists made the discovery while examining the well-preserved fossil of a hard-shelled species called a trilobite.
The ancestors of spiders and crabs lived in coastal waters during the Palaeozoic era, between 541 and 251 million years ago.
