Truly Underground Art

Known as the Underbelly Project, the works are entirely inaccessible by traditional -- or legal -- means. However, urban explorers and those adventurous enough to venture into the abandoned subways will likely be treated to quite a show.

"It is one of the largest shows of such pieces ever mounted in one place, and many of the contributors are significant figures in both the street-art world and the commercial trade that now revolves around it. Its debut might have been expected to draw critics, art dealers and auction-house representatives, not to mention hordes of young fans. But none of them were invited.

In the weeks since, almost no one has seen the show. The gallery, whose existence has been a closely guarded secret, closed on the same night it opened."