[Image: Tunneling beneath Chicago; view larger!].

Due to Chicago's ongoing TARP project—its Tunnel And Reservoir Plan—there are now "109.4 miles of tunnels bored beneath the Chicagoland area." According to Tunnel Business Magazine, this massive network of new subterranean space includes "deep tunnels, drop shafts, near-surface connection and control structures and dewatering pump stations," all embedded beneath the city. I would love to see Michael Cook sent there as a project photographer.

Until then, the above image shows us TARP's first phase in action, with a tunneling machine breaking through and expanding the artificial caverns that now resonate below the streets of greater Chicago. TARP's second phase—the so-called Chicago Underflow Plan—kicked off back in 2008, its work "consisting of [the] mining and construction of several reservoirs," vast hollows that will occasionally fill with storm runoff and rain, reknitting urban hydrology from below.

(Thanks to Anya Domlesky for the link! Download back issues of Tunnel Business Magazine here).