Gilding: There has been a boom in "gilding" in NYC over the past few years. Perhaps someone has invented a new, cheaper process, or hired a new, better salesman, or it was just because of the economic boom?

Terra Cotta: Our bible for this series was "Terra-Cotta Skyline" (the author graciously allowed us to quote from it as desired) and the first thing the we realized after reading it is that there's a LOT more terra cotta in NYC then we thought. It turns out to be the key ingredient in most of our favorite buildings.