Add Yahoo as a preferred source to see more of our stories on Google. The rose window in the narthex, Strasbourg Cathedral, Strasbourg, Alsace, France. There's something strange about the ...

The best way to understand glass is to understand how it is made. The first step to make glass requires heating up a mixture of minerals – often soda ash, limestone and quartz sand – until they melt ...

There's something strange about the stained-glass windows of medieval buildings: They tend to be thicker at the bottom than at the top. Many believe this is because glass is actually a liquid that has ...