Description:Foundry workers in Normandy, France face searing heat as they mix metal for the last of Notre Dame Cathedral's eight new bells. The Paris landmark will celebrate its 850th anniversary in 2013 and the new bells are a sort of architectural birthday gift. Foundry President, Paul Bergamo says a lot of research went into reproducing the sound quality of the bells that were in the cathedral's belfry during the French Revolution.(1:16)