The geology of a place is not understood only by observing rock outcrops and boulders in natural areas! A lot of information on the type of rocks present and their characteristics can be obtained from local monuments, such as churches, statues and ancient palaces, where geology and art merge. Among the best examples of "urban geology" we certainly find the Basilica of the Madonna di Tirano, located in the town of the same name, whose construction began in 1504 using local stone materials. It is the most important example of Renaissance architecture in Valtellina. 
The history of the Basilica of the Madonna di Tirano begins, as usual for Marian shrines, with a miracle: according to the anonymous chronicler of the Book of Miracles, at the dawn of September 29, 1504, the Virgin Mary appeared to the nobleman Mario Omodei who was leaving for some of his lands just outside of town, and asked him to build a temple dedicated to her in the place of their meeting. 
Local white marble was used for the façade, especially for the portal and the windows; the rock was extracted from an existing quarry near the hamlet of Cologna, in the locality of "Pomo" ("El Pum" in the local dialect). The architrave of the façade consists of a serpentine block, while the dome and the lantern were built with stones and marble from the local quarries of Pomo, Valdichiosa and Grania, also used for the completion of the bell tower. Inside the Basilica there are several marble statues, produced with marble from Val Malgina (in the territory of Teglio) worked in Como and then brought back to Tirano. 
Inside the Basilica stands the organ, a gigantic work with 2200 pipes (one of the biggest in Europe!), resting on eight columns of red Arzo marble of Canton Ticino. The main altar was built with black Varenna marbles inlaid with other polychrome marbles in 1748 by Giovanni Battista Galli, a craftsman from Clivio, to whom we owe not only the balustrades of the same altar, but also those of the chapel of the Apparition. 

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• http://www.lombardiabeniculturali.it/architetture/schede/1n110-00012/