Santi Cosma e Damiano was originally a Roman Catholic church affiliated with an Augustinian convent, it is now Greek Orthodox church.
Of the 12th-century Romanesque construction, only the bell-tower remains; the present facade and interiors mainly date to a reconstruction in the 18th century. The main altar (18th century) in polychrome marble has statues by Antonio Callegari and altarpiece by Giambettino Cignaroli and a 16th-century Ark of St Tiziano. Adjacent to the church is a 15th-century cloister. In 1923, at the instigation of a local poet Angelo Canossi, the names of the Italians who died in the war were inscribed in the columns.
References:
The Externsteine (Extern stones) is a distinctive sandstone rock formation located in the Teutoburg Forest, near the town of Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. Archaeological excavations have yielded some Upper Paleolithic stone tools dating to about 10,700 BC from 9,600 BC.
In a popular tradition going back to an idea proposed to Hermann Hamelmann in 1564, the Externsteine are identified as a sacred site of the pagan Saxons, and the location of the Irminsul (sacral pillar-like object in German paganism) idol reportedly destroyed by Charlemagne; there is however no archaeological evidence that would confirm the site's use during the relevant period.
The stones were used as the site of a hermitage in the Middle Ages, and by at least the high medieval period were the site of a Christian chapel. The Externsteine relief is a medieval depiction of the Descent from the Cross. It remains controversial whether the site was already used for Christian worship in the 8th to early 10th centuries.
The Externsteine gained prominence when Völkisch and nationalistic scholars took an interest in the late 19th and early 20th centuries. This interest peaked under the Nazi regime, when the Externsteine became a focus of nazi propaganda. Today, they remain a popular tourist destination and also continue to attract Neo-Pagans and Neo-Nazis.