<http://schema.org/keywords>
"trees, switzerland, mountains, tree, fall, snow, swiss, mountain, snowing, hill, suisse, snowy, berge, schweiz, berg, baum, b\u00C3\u00A4ume, schnee, scheefall, clouds, forest, sky, white, winter"^^<http://www.w3.org/2001/XMLSchema#string>
<https://marketplace.500px.com/photos/19489139/snowy-landscape-schnee-b%25C3%25A4ume-auf-h%25C3%25BCgel-mit-haus-by-eric-peter>