Church frescos in Denmark
Church wall paintings (Danish: kalkmalerier) are to be found in some 600 churches across Denmark, no doubt representing the highest concentration of surviving church murals anywhere in the world. Most of them date back to the Middle Ages and were uncovered by Jacob Kornerup (1825–1913) who carried out restoration work in 80 churches across the country towards the end of the 19th century.
Source: Wikipedia — Church frescos in Denmark (CC BY-SA 4.0)