<http://schema.org/keywords>
"train, railway, paris, waiting, subway, stairs, station, metro, rail, pentax, tren, metropolitan, wide angle, cite, estaci\u00C3\u00B3n, espera, pentax k5, 13mm, sigma 10 - 20 mm"^^<http://www.w3.org/2001/XMLSchema#string>
<https://marketplace.500px.com/photos/20817657/cit%25C3%25A9-by-rafael-juliana>