World's oldest leather shoe, as old as the Indus Valley Civilisation has been found in perfect shape 5,500 years after it was crafted in a cave in Armenia.

A group of archaeologists and scientists stumbled on the shoe made of single piece of leather which was shaped according to user's feet.

Scientists are wondering what kept the shoe in such perfect condition that even its laces are intact. They found grass inside it but they are not sure whether it was used to keep the feet warm or maintain its shape.

The team is still trying to solve the puzzle whether the small footwear belonged to a man or a woman.

It dates back to 3500 BC when seeds of Indian Civilisation were being sown in the Harappa valley, findings published today in the online edition of science journal 'Public Library of Science' said.

It was found by an Armenian PhD student Diana Zardaryan of the Institute of Archaeology, Armenia, in a pit that also included a broken pot and sheep's horns.

The area where the footwear was discovered is located in Vayotz Dzor province of Armenia, close to Nakhichevan region on the border of Armenia, Iran and Turky.

According to the research paper "stable, cool and dry conditions" in the cave were responsible for preserving it in exceptional condition.

The team also found various objects which included large containers, many of which held well-preserved wheat and barley, apricots and other edible plants.

"The preservation was also helped by the fact that the floor of the cave was covered by a thick layer of sheep dung which acted as a solid seal over the objects, preserving them beautifully over the millennia," Lead author Dr Ron Pinhasi from University College Cork, Ireland said.

When the shoe was found the team of scientists thought that it could be about 500-600 years old. But detailed scientific analysis revealed that it was more than 5500 years old making it the oldest shoe of the planet.