Later this month, thousands will gather at Chichen Itza Mayan archaelogical site, for an amazing event at this modern Wonder of the World.

On Spring Equinox, March 21, they will witness the astounding accuracy of Mayan astronomy in the architecture of the Pyramid of Kulkulkan.

The Equinoxes - when the number of hours in the day is equal to those at night - were sacred to the Mayans, whose beliefs were based around calender cycles.

During the Equinox, the sun's rays on the pyramid make seven triangles that look like the body of a serpent 111 ft (34m) long, moving down the side of the pyramid and joining a huge, carved stone serpent head at the bottom.

The phenomenon can be viewed in Chichen Itza for four days, so if the weather isn't good or you can't get there on one day, you still have more options. This year it is visible from the 20-23 of March. Get there before 3 pm. The show lasts about an hour. Be prepared for a big crowd!