Fall equinox
Stonehenge
A woman dances as druids, pagans and revelers gather at Stonehenge, hoping to see the sun rise, as they take part in a autumn equinox celebration at the ancient neolithic monument on Sept. 23, 2017, in Wiltshire, England.
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 Sept. 21, two days ahead of the 2019 fall equinox.
El Salvador
Indigenous women participate in a Mayan ceremony marking fall equinox at the Cihuatan ruins in Aguilares, El Salvador.
London
Druids celebrate the autumnal equinox on Primrose Hill in London. The ceremony is one of three events staged by the order with the spring equinox ceremony at Tower Hill and the summer solstice held at Stonehenge.
Vilnius, Lithuania
People watch the autumn equinox celebration on the embankment of the Neris River in Vilnius, Lithuania, on Sept. 20, 2019.
Banff National Park
A full moon rises over Vermilion Lakes at Banff National Park in Canada. The full moon closest to the fall equinox is often called the harvest moon.
Dorset, England
The sun rises behind Corfe Castle, not far from the English Channel.
Oregon
Elliott Cely, 2, of Portland, plays in a pumpkin patch at the Rasmussen Farms on Sept. 22, 2010, in Hood River, Ore, on the autumnal equinox.
Tuesday marks the fall equinox: the end of summer and start of fall. Here's what to know about it, plus a gallery of fall equinox images over the years.