As Autumn Begins

In two days we celebrate the autumnal equinox. Almanac.com lists lists some traditions: At Machu Picchu in Peru, an ancient stone monument called Intihuatana—which means “Hitching Post of the Sun”—serves as a solar clock to mark the dates of the equinoxes and solstices. In Mexico, the Mayans built a giant pyramid called Chichen Itza. On the equinoxes, it looks as if …