Chicagohenge sunset, Chicago, Illinois

The city grid delivers this celestial phenomenon. Chicagohenge

During the fall and spring equinox, the celestial phenomenon known as Chicagohenge occurs when the sun rises or sets directly between the buildings lining Chicago's east- and west-facing streets. The city's almost perfectly aligned grid is responsible for the event.

During the equinox, the Northern and Southern hemispheres receive an equal amount of sunlight, and the sun rises and sets directly to the east and west. As it happens, Chicago's grid is aligned with the cardinal directions on a compass, a handy fact to know anytime you're walking in the city.

It might be easy to lose touch with the natural cycles of the planet when you live in a concrete jungle, but at least twice a year, Chicagohenge reminds city dwellers exactly where this third rock from the sun is spinning.