Solo, The Loop & the 'L' works.
Riding the elevated 'L' as it clatters around the wooden-platform curve at Quincy and threads between the terra-cotta facades — and walking the canyon below from the Rookery's Frank Lloyd Wright light court to the Marquette Building's mosaic lobby — is the quintessential Chicago sensory experience, and it costs little more than a transit fare. The honest catch is that it's a working business district: alive and architectural on weekdays, but much of it goes quiet at night and on weekends.