From Information Week: Solar-Powered Nanotech-Purified Air In Medieval Churches.
The glaziers who created gold-painted stained glass windows for medieval churches in Europe inadvertently developed a solar-powered nanotech air-purification system.
According to Zhu Huai Yong, an associate professor at Queensland University of Technology in Australia, the gold paint used in medieval-era stained glass windows purified the air when heated by sunlight.
"For centuries people appreciated only the beautiful works of art, and long life of the colors, but little did they realize that these works of art are also, in modern language, photocatalytic air purifier with nanostructured gold catalyst," said Zhu in a statement. [continue]
Link found at The Cranky Professor.