Blue tiles are pretty common in Arabic culture and were brought that way to the southern parts of Spain and Portugal, where they are called Azulejos from the Ar

Blue tiles are pretty common in Arabic culture and were brought that way to the southern parts of Spain and Portugal, where they are called Azulejos from the Arabic الزليج. Unfortunately some of them are a radiation hazard, because the blue color is made out of radiocactive cobalt. A blue tile also plays an important role in the short film Zima Blue, which I cannot recommend highly enough - because of the story and its aesthetics.