A quarter of the stone surface of Stonehenge is inaccessible to conventional archaeological survey techniques such as laser scanning due to the dense coverage of lichen. This project will aim to: (i) create a novel method, combining machine learning and surface imaging techniques such as photogrammetry, to reveal carvings that may be hidden by lichen covered stone surfaces; and (ii) verify any findings using a subsurface imaging technique such as terahertz imaging. The project will answer the question of whether there are more prehistoric rock carvings hidden by lichen on Stonehenge, and whether, with only an understanding of the topography of the lichen, we can find these carvings. The results will be of use for further unravelling archaeological detail at Stonehenge, and aid conservation, presentation and management of the site. Outcomes will have wider applicability as a rapid non-invasive technique for measuring and monitoring the microtopography of vegetation-covered stone surfaces at other monuments and historic buildings.