Rainbows might well be the most beautiful things you can see outside, but what if you could bring them inside? This is the idea artist Kimsooja. She uses a thin translucent diffraction film to cover the windows of a glass house called Palacio de Cristal, Parque del Retiro, in Madrid. light shines in, the film creates rainbows and the mirrored floor reflects them all around, filling the entire place with vibrant colors. A must see if you ever get the chance because, how often do you have the opportunity to stand in between rainbows!