(was going to post this in "More than Just Trains" but did not want to cause any consternation. Mods please feel free to move it. "Catenary (from the Latin catena, or chain) is the name given to the curve formed when you hang a piece of chain from two points. That’s exactly the process pre-modern builders used to determine the angle necessary for a cathedral’s arch to support its own weight. Even Gaudi used the chain method to form his iconic vaults, well into the 20th century, though generally we associate the process with Medieval architects." More: http://www.msnbc.msn.com/id/47651131/ns/technology_and_science-tech_and_gadgets/#.T8t8elLHle4 Anyway, i thought it would be fun to share.
