What the equinox 'henge' effect tells us about U.S. cities

The fall equinox brings shorter days, and the change of seasons. In some U.S. cities, it's also a chance to witness the striking alignment between the sun and Earth, as sunrises and sunsets align with city streets running east and west. It's a modern version of ancient observances of a celestial shift, like sunrise at Stonehenge.

"Humans still connect with how special it feels," says Geoff Boeing, who studies city design as the chair of the Department of Urban Planning and Spatial Analysis at the University of Southern California.

"The things we built helped us to frame the universe in a certain way," Boeing adds.

In this case, that framing is literal. Take Chicago, for instance.