I’m on the “L,” Chicago’s elevated train, rumbling past building after building, 20 feet off the ground, when a little voice in my left ear says, “OK, just before we turn the corner, be on the lookout for the third shell medallion from the end, and tell me what you see.”

I’m on the lookout indeed, and as the train starts to hug the corner around the LeMoyne Building, I watch the lineup of ornaments on its exterior. And then I see it: The shell above one of the exterior pillars is upside-down. “Now you have to wonder,” the voice in my ear continues. “Did they not notice, or was it a joke for the train people? I’m going with a joke.”

The voice belongs to Lynn Hensel, a docent on this Chicago Architecture Foundation tour, who’s speaking to me through a little earpiece connected to her own microphone and transmitter. Of the 85 tours the foundation leads on foot, by boat and by Segway, this is one of the newest. And I’m taking it because I’m intrigued by the idea of getting a unique perspective on the city’s boisterous architecture from a vantage point offered by what less urban-minded folks might consider just a noisy eyesore. In the so-called City of Big Shoulders, this is like crawling around at knee height.

Hensel weaves her views on building motifs, materials and styles – from the classic Chicago school to neoclassical, modernist and postmodern – together with stories of the L’s development from a series of disparate lines into a unified system in the late 1890s. At the center of that effort was Charles Tyson Yerkes, who apparently strong-armed property owners into giving their permission for the crucial center loop to be built. His tactics involved bribes and the use of “vamps” who seduced and then blackmailed.

The tour focus, though, is on the buildings. And what buildings! Chicago’s forward-thinking architecture no doubt stems from the city’s near-destruction in the Great Fire of 1871, and Hensel shows us one stunning structure after another, sometimes closer than you could get any other way short of moving in.

For another perspective, that afternoon I board the foundation’s popular Chicago River cruise. Docent Barry Aldridge is even more entertaining, peppering the ride with a catchphrase that he thinks best sums up the valuable role of the buildings’ designers: “Kiss your architect.”

Like Hensel and her history of the train, Aldridge sprinkles his tour with tales not only of the development of Chicago’s riverfront, but also with the development of the river itself. Perhaps most impressively, the city reversed the flow of water in 1900 to reduce industrial pollution, building a canal that caused gravity to pull clean water from Lake Michigan into the river rather than vice versa. “Some people say that what we flush in Chicago they end up drinking in St. Louis,” he deadpans, “but the river is much cleaner than it used to be.”