Marine archaeologists and terrestrial surveyors in the Outer Hebrides have identified a two-mile-long processional route paved with locally sourced blue-tinted basalt. The path leads from an inland stone circle directly to a natural sea cave, which researchers now believe was the site of an Iron Age "Blessing of the Deep" festival. Fragments of shale bracelets and polished sea-glass were found along the route, likely dropped by ancient pilgrims.
The orientation of the path suggests it was used during the spring equinox, when the setting sun aligns with the cave's entrance. This ritual infrastructure points to a sophisticated maritime culture that celebrated the sea as a source of both peril and plenty, using organized festival circuits to bind coastal communities together through shared spiritual practices and the maintenance of sacred landscapes.