For thousands of years they have been the centre of mystery and ritual.

Now more secrets are about to be revealed by hidden ancient stone circles in the Outer Hebrides.

A project is to lead to their rediscovery.

New funding from Historic Environment Scotland (HES) will allow researchers at the University of St Andrews to discover the secrets of the concealed stone circles on the Isle of Lewis.

A pilot project led by Dr Richard Bates of the School of Earth and Environmental Studies at the university, with a team of archaeologists and geophysicists from Bradford University and Trinity St David, University of Wales, previously explored the area near the famous Calanais (Callanish in English) standing stones.

Community volunteers helped to survey one of the satellite stone circle sites close to Calanais and the team of experts was able to create images of the buried stone circle and also discover that a major lightning strike had occurred at the centre of the stone circle.

The new project will allow the team and community to extend the investigations to the other stone sites and importantly to map the Neolithic landscape buried beneath the peat and submerged offshore.

Urras nan Tursachan, has been awarded a £19,920 from HES for a community project to train local volunteers to survey and record the coastal landscape at Calanais, the intertidal zone and the waters of Loch Roag. Researchers will aid the project to use geophysics and traditional survey techniques to gain new insights into the site.

Dr Richard Bates said: “We are extremely pleased to be working with Urras nan Tursachan (UNT) on this exciting new project. The landscape holds so many fascinating secrets that we hope can be addressed through a combination of geophysical remote sensing and boots-on-the-ground with the local community volunteers.”

The project is one of 18 community-based projects receiving funding from Historic Environment Scotland (HES) to protect, promote or engage with Scotland’s coastal or waterway heritage as part of its Coast and Waters Heritage Fund.

Grants of £3,000 to £20,000 from an overall fund of £194,349 have been awarded to projects which deliver benefits to the local community through outreach and educational activities, repairs to stabilise historic or marine structures, developing traditional skills and increasing understanding of Scotland’s coasts and waters heritage. Funding has also been awarded to projects which are developing and implementing measures to enhance resilience and adapt to climate change.

The Coasts and Waters Heritage Fund is a one-off competitive fund which launched in March to celebrate Scotland’s Year of Coast and Waters.

The world-famous Callanish Stones attract tens of thousands of visitors each year.

The giant megaliths – next in importance to Stonehenge – are said to be older than the pyramids in Egypt.

The stones - set in the shape of a Celtic cross - also featured in the blockbuster Brave

Callanish predates Stonehenge and was an important place for ritual activity for at least 2,000 years.

The main stone circle site dates from between 2900 and 2600 BC. It, and the surrounding circle satellites, is one of the most important surviving complexes of early prehistoric ritual monuments in Europe.

Peat preserved the site, leaving the taller stones visible, which revealed the rest of the site when the peat was removed in 1857. Two years before that it became one of the first historic sites to be taken into state care.

The main complex contains 50 stones in a cross shaped setting.

The inner circle at Callanish has 13 stones, the tallest of which is four metres high. It is thought that the alignments of the various stones, unlike those of other ancient monuments which are in line with the sun, may have been used to mark significant points in the lunar cycle.