So far acoustic measurements have been performed at three sacred sites in northern Finland, namely, two prehistoric rock paintings (5200 to 1000 BC) and one Sámi offering site from the historical period (circa 1100 to present). All of these sites are located on steep cliffs rising on the shores of narrow canyon-like lakes, where the water levels have remained constant throughout the past millennia. As the cliffs fall straight into the water, the sites can only be accessed by boat or, during the winter, over the frozen surface of the lake.