AMHERST, Mass. (WWLP) — Monday marked the start of Spring and many observed the equinox over at the University of Massachusetts Amherst’s Sunwheel.

The exact time of the equinox this year was 5:24 p.m. These Sunwheel events mark the astronomical change of seasons when days and nights are nearly equal in length everywhere in the world, which is the source of the term equinox for “equal night”.

22News stopped by to learn a little bit more about the Sunwheel.

“So the Sunwheel is something we call a calendar device, we see the sun actually as it changes throughout the year,” explained UMass Amherst Professor of Astronomy, Stephen Schneider.

Other structures around the world mark this astronomical change, such as the pyramid at Chichen Itza in Mexico.