From NPR · · 1m 50s
Why the sun aligns with city streets twice a year
The equinox creates striking solar alignments in grid-planned U.S. cities, connecting modern urban design to ancient celestial observation.
In brief
The equinox creates striking solar alignments in grid-planned U.S. cities, connecting modern urban design to ancient celestial observation. Cities built on compass-aligned grids accidentally recreate ancient astronomical alignments twice yearly, reminding us that human-made structures still frame our relationship with…
The sun aligns with city streets
Twice a year at the equinox, sunrises and sunsets align perfectly with east-west streets in grid-planned U.S. cities, creating a striking celestial effect.
Chicago's famous Chicagohenge moment
In Chicago's downtown, tall buildings frame the rising and setting sun on east-west streets like Kinzie and Madison, amplifying the effect through urban geometry.
When the 2026 fall equinox arrives
The fall equinox occurs on September 22, 2026, in the evening U.S. time, marking roughly equal hours of day and night as autumn begins in the Northern Hemisphere.
Other cities with grid alignments
Washington D.C., Phoenix, and Denver also offer good chances to spot henge moments because their streets follow compass points like Chicago's do.
Ancient cities planned the cosmos
For thousands of years, early cities were designed as cosmological maps with points corresponding to stars, like Tenochtitlan, the Aztec precursor to Mexico City.
“their cities would be designed almost like cosmological maps to follow it, where you could have points in the city that corresponded to certain stars”
Modern grids are accidental astronomy
Today's grid-planned cities weren't designed for celestial alignment, but their compass orientation creates the same effect anyway, once or twice yearly.
“Even if we didn't do it intentionally, we're still getting the same side effects at least once or twice a year.”
Why grids spread across America
Compass-aligned grids became standard during 19th-century westward expansion because they made it easier to buy, sell, and map infrastructure like railroads.
Not all cities align with the equinox
Manhattan and San Francisco follow local geography instead of compass points, so their henge effects occur on different dates than the equinox.
Safety tips for equinox photography
Stay on sidewalks when photographing the effect, and watch for glare on east-west streets that can cause traffic backups and reduce visibility.
“Don't walk out in the middle of the street to be able to take the perfect photo. You can do this from the sidewalks, on the side.”
Here's the gist
Cities built on compass-aligned grids accidentally recreate ancient astronomical alignments twice yearly, reminding us that human-made structures still frame our relationship with the sky.
