With the downfall of the economy and all the hundreds of projects trimmed or cut this year because of it, there are a lot of empty lots out there, just sitting there reminding us of what could have been. And for those projects that got started and ran out of money, we have that favorite phrase of ours, "accidental architecture." It was both these types of failed architecture that got Irene Cheng and her husband Brett Snyder thinking. Using funding from the Val Alen Institute's New York Prize Fellowship, the duo created an iPhone application called Museum of the Phantom City, which looks at all the various exciting projects that were planned for New York, but were never realized due to funding, contract failures, complete infeasibility, or any of the other million reasons that result in these ideas' disappearances. Using GPS, you can use the app to wander around the streets of NY and absorb a little history about what never was as you come to it, along with some interactive bits surrounding these invisible sights. But besides being just something interesting to play with, the app also has value in realizing the steps a city takes on its road through history:

"If everything that gets proposed is the result of a familiar process, it will produce familiar results," [City University of New York's Michael Sorkin] said on Wednesday. "So radicalizing the discourse is a way to open up the debate.

"In the history of New York, projects that were not built were absolutely formative in the development of the city," he added.