The discovery of an ancient piece of aluminium is being hailed as evidence that aliens visited Earth 250,000 years ago.

The mysterious hunk of metal was found in Romania during the 1970s, when the country was under communist rule.

Now tests at a lab in Lausanne, Switzerland, have revealed that the strange fragment of metal is made up of 90 percent aluminium and is 250,000 years old.

Aluminium was not produced by mankind until about 200 years ago, so the discovery of the large chunk that could be up to 250,000 years old is being held up as a sensational find.

Gheorghe Cohal, the Deputy Director of the Romanian Ufologists Association, told local media: "Lab tests concluded it is an old UFO fragment given that the substances it comprises cannot be combined with technology available on Earth."

Builders working on the shores of the Mures River not far from the central Romanian town of Aiud found the objects about 33 feet under the ground, where it was buried alongside two bones.

It was quickly determined that the two large bones belonged to a large extinct mammal that died between 10,000 and 80,000 years ago, but experts were stunned to find out that the third object was a piece of very lightweight metal and appeared to have been manufactured.

However, local historian Mihai Wittenberger said the object is actually a metal piece from a World War II German aircraft, although this does not explain the age of the artifact.

The metal object has now gone on display in the History Museum of Cluj-Napoca with its full history causing heated speculation after it was noted that museum officials had added a sign saying: "origin still unknown."

This story first appeared in the Sun.