In Finland, near the canyon lakes of Julma-Ölkky, Somerjärvi and Taatsijärvi, steep rock cliffs produce distinctive acoustic spaces. On these cliffs, prehistoric rock paintings (5200—500 BC) as well as an ancient Sami offering site (cf. 1100—AD) can be found. Ethnographic sources describe that the Sami used to sing and listen to echoes while making offerings there. This paper presents the results of an archaeoacoustic project that seeks to explore the role of sound in the development and use of these archaeological sites. The applied methods include multichannel impulse response recording, angle of arrival estimation of early reflections, spectrum analysis, digital image processing, and 3D laser scanning. On the basis of the analyses, we have concluded that the cliffs that have been painted or held as sacred are efficient sound reflectors. They create discreet echoes and, accordingly, phantom sound sources. Especially at the Värikallio cliff, the sound appears to emanate directly from the painted figures. These results, together with previously unnoticed drumming figures in the Värikallio painting, provide a clue to the significance of the sound rituals at these sacred sites.