<strong>Earth:</strong> Twice a year, the terminator that divides night from day on Earth is a straight north-south line. We call those the equinoxes. There's one in the spring (or vernal) equinox. The other is the fall (or autumnal) equinox, which is most associated with harvests. Click through the gallery to see previous autumnal equinox celebrations and settings around the world:
Earth: Twice a year, the terminator that divides night from day on Earth is a straight north-south line. We call those the equinoxes. There's one in the spring (or vernal) equinox. The other is the fall (or autumnal) equinox, which is most associated with harvests. Click through the gallery to see previous autumnal equinox celebrations and settings around the world:
NASA images
<strong>Yucatan, Mexico:</strong> People watch the sun rising through the door of the Seven Dolls Temple in the Maya archaeological site of Dzibilchaltun in Yucatan State, Mexico, on September 21, two days ahead of the 2019 fall equinox.
Yucatan, Mexico: People watch the sun rising through the door of the Seven Dolls Temple in the Maya archaeological site of Dzibilchaltun in Yucatan State, Mexico, on September 21, two days ahead of the 2019 fall equinox.
Hugo Borges/AFP/Getty Images
<strong>Vilnius, Lithuania:</strong> People watch the autumn equinox celebration on the embankment of the Neris River near King Mindaugas' Bridge on September 20, 2019.
Vilnius, Lithuania: People watch the autumn equinox celebration on the embankment of the Neris River near King Mindaugas' Bridge on September 20, 2019.
Mindaugas Kulbis/AP
<strong>London:</strong> Druids celebrate the autumnal equinox on Primrose Hill in London.
London: Druids celebrate the autumnal equinox on Primrose Hill in London.
Peter Macdiarmid/Getty Images
<strong>Glastonbury, England:</strong> A lone paraglider enjoys the early morning mist that lingers in fields as the autumn sun rises near Glastonbury, southwest of Bath.
Glastonbury, England: A lone paraglider enjoys the early morning mist that lingers in fields as the autumn sun rises near Glastonbury, southwest of Bath.
Matt Cardy/Getty Images
<strong>Wiltshire, England:</strong> A woman dances as druids, pagans and revelers gather at Stonehenge for the sunrise.
Wiltshire, England: A woman dances as druids, pagans and revelers gather at Stonehenge for the sunrise.
Matt Cardy/Getty Images
<strong>Portland, Oregon:</strong> In some places, autumn colors time their arrival with the fall equinox. Tree branches laden with the multicolored leaves greet the equinox in Portland.
Portland, Oregon: In some places, autumn colors time their arrival with the fall equinox. Tree branches laden with the multicolored leaves greet the equinox in Portland.
Don Ryan/AP
<strong>Banff National Park, Canada:</strong> A full moon rises over Vermilion Lakes. The full moon closest to the fall equinox is often called the harvest moon.
Banff National Park, Canada: A full moon rises over Vermilion Lakes. The full moon closest to the fall equinox is often called the harvest moon.
Alan Dyer/VW PICS/UIG/Getty Images
<strong>Aguilares, El Salvador:</strong> Indigenous women participate in a Mayan ceremony marking fall equinox at the Cihuatan ruins.
Aguilares, El Salvador: Indigenous women participate in a Mayan ceremony marking fall equinox at the Cihuatan ruins.
Luis Romero/AP
<strong>Dorset, England:</strong> The sun rises behind Corfe Castle, not far from the English Channel.
Dorset, England: The sun rises behind Corfe Castle, not far from the English Channel.
Andrew Matthews/PA Images/Getty Images