★ Wallpaper printed with invisible ink glow when placed under an ultraviolet light.

★ There are around 30,000 "love hotels" in Japan, where guest can pay by the hour to escape the daily grind of their lives and enjoy some well earned respite. With so many of them around, love hotels go to great lengths to attract customers with their unique interior design philosophies. Here are some examples.

★ Art that only appears when ultraviolet light is turned on are extremely prevalent in love hotels. It’s also a good way of telling whether the sheets are clean.