Top 5 ‘Henges’: When Astronomy Meets Architecture

Manhattanhenge New York City Sunset

Move over, Stonehenge. You’re not the only place where the rising sun combines with architecture to create a stunning visual phenomenon. Many of these events around the world take place on solstices—when the sun is the farthest north or south from the equator—and equinoxes, when day and night are nearly the same length. Others occur at different times throughout the year. 

Philadelphia experiences its own Phillyhenge this Friday (April 6), when the sun will appear at the west end of Market Street around 7:30 p.m. (Hear more from our chief astronomer, Derek Pitts, on WHHY’s Skytalk.) 

The most famous henge in the U.S. occurs in Manhattan, home to more than 1.6 million people and a tightly packed street grid system. Manhattanhenge (we can thank Neil deGrasse Tyson for coining that term) happens twice a year when the setting sun aligns precisely with the grid, “simultaneously illuminating both the north and south sides of every cross street,” Tyson says. “A rare and beautiful sight.” Each Manhattanhenge has two days of Instagram-worthy sun showings: on the first day, half of the sun’s disk can be seen just above the horizon; on the next, the full disk is visible. 

Several other North American spots have a “cityhenge” of their own, including Chicago and Toronto. To find one near you, use an app such as the Photographer’s Ephemeris or check with your local planetarium.

There’s no more famous henge than this prehistoric circle of standing stones on Salisbury Plain in Wiltshire, England. Constructed some 4,500 years ago by ancient Britons, its purpose is still a mystery. But one thing is clear: At sunset on the winter solstice and at dawn on the summer solstice, the sun aligns with the concentric rings and creates a dazzling effect, leading many archaeologists to speculate that Stonehenge was constructed to serve as an astronomical calendar.

Even older than Stonehenge is Newgrange, a Stone Age monument in County Meath, Ireland. Built around 3200 B.C., Newgrange is a passage tomb, a style of tomb in which a long passage and several chambers are covered with a mound of earth or a cairn. Newgrange draws crowds every winter solstice, when the rising sun aligns precisely with an opening above the entrance door, illuminating the chamber floor.

Chichen Itzá
The ancient Maya in Mexico’s Yucatán Peninsula devised an even more dramatic way to mark the equinoxes at Chichen Itzá, a Mayan city built beginning around A.D. 600. Each afternoon on the spring and autumn equinoxes, a snake made of sunlight appears to slither down the steps of the El Castillo pyramid, a sight that draws huge crowds. Many scholars believe the wriggling snake represents the serpent god Kukulkan. 

Abu Simbel
Not all prehistoric light shows are connected to the solstice or equinox. At the ancient Egyptian site of Abu Simbel, built beginning around 1260 B.C., the sun aligns with the main temple on two important days of the year: The anniversary of Pharaoh Ramses II’s birth (February 22) and his coronation (October 22). Sunlight floods the temple’s inner sanctum, illuminating statues of sun gods and the pharaoh. The rays never reach a statue of Ptah, a god of darkness.