Inciting a latent fluorescence
This Chicago alley is listed on the National Register of Historic Places because it's one of the few extant examples of end grain wood paving. It was restored in 2011 and the original creosote laden cedar pavers were replaced with a different wood, black locust, because of its intrinsic rot resistant properties. Incidentally, black locust also fluoresces under ultraviolet light. I recorded myself visiting the alley one night, planing a section, and watching the unoxidized surface fluoresce under an ultraviolet flashlight.