The oldest human footprints, dating back to more than 3.5 million years ago, urgently need protection, according to experts.
The 23m-long track of footprints is pressed into a volcanic ash bed in Laetoli, which is a few hours drive into the Ngorongoro National Park in northern Tanzania.
These important tracks reveal clues to how our ancient human ancestors evolved from walking on four limbs to walking upright millions of years ago.
In 1995, the tracks were covered up with a protective coating, but exposure to the weather and the growth of plants and trees have eroded the coating. Experts reporting at an international conference last month say the footprints are now more exposed to erosion, livestock and humans and are in danger of being destroyed forever.
Some scientists have suggested that a museum be built over the footprints or that they be dug up and transported to one of Tanzania's museums in, for example, Dar es Salaam, the country's capital.
'The Laetoli footprints give us direct information about the early appearance of one of humanity's defining characteristics - our upright stance,' said Prof Chris Stringer, human origins expert at the Natural History Museum.
'It is possible that the excavated prints are only part of many such trails that await discovery, in which case their exposure and display, either at Laetoli or in a separate museum, would give present generations of Tanzanians and tourists a glimpse of this unique record.'
'However, the long-term preservation of the site must be paramount, so that future generations can continue to research there.'
The footprints were discovered in 1978 by Mary Leakey and her team. The footprints may have belonged to Australopithecus afarensis, an early human relative whose fossil remains have been found in Eastern Africa.