<http://schema.org/keywords>
"germany, deutschland, essen, bochum, nordrheinwestfalen, nrw, moon, fullmoon, blue, ray of light, Light exhibition, europe, nobody"^^<http://www.w3.org/2001/XMLSchema#string>
<https://marketplace.500px.com/photos/22003853/full-moon-by-seiha-heng>