A large wood-and-straw artwork burns on the Northern Hemisphere's autumnal equinox during the 2006 International Festival of Fire Sculptures in the Lithuanian capital of Vilnius—one of countless cultural events marking the first day of fall each year.
Featuring roughly four-story-tall representations of beasts from local legends and mythology, the roaring celebration, which began in 1991, commemorates Grand Duke Gediminas, who ruled Lithuania in the 14th century and is traditionally seen as a defender of the country's pagan heritage.
Photograph by Petras Malukas, AFP/Getty Images
Pagan Procession on Autumnal Equinox
Modern-day Druids—who, like their ancient forebears put great store in solar milestones—mark autumnal equinox 2009 on Primrose Hill in London. For the vernal equinox, the pagan parade reconvenes on Tower Hill, site of the Tower of London. At summer solstice Druids decamp to Stonehenge.
Crowds gather around El Castillo at Mexico's ancient Maya city of Chichen Itza on the autumnal equinox of 2005.
Hitting the pyramid at just the right angle, sunlight casts an undulating shadow on the side of a staircase each equinox. When the shadow aligns with a monumental stone head at El Castillo's base, a titanic, glowing serpent is born.
Each autumnal equinox and vernal equinox, hundreds gather for the "light miracle" at San Juan de Ortega monastery in northern Spain (pictured, the phenomenon on March 21, 2010). During the semiannual spectacle a narrow shaft of light falls squarely in a relief sculpture of the Virgin Mary.
Maya priest Gustavo Pineda, front left, commemorates the 2007 autumnal equinox in Los Planes de Renderos, El Salvador.
The ancient Maya—whose empire thrived between A.D. 250 and 900 in what are now Mexico and Central America—built observatories and, via astronomy and mathematics, learned to accurately predict equinoxes and other celestial phenomena.