Friday is the Winter Solstice in the northern hemisphere.
It's also a day that's generated a lot of buzz among historians and new age spiritualists. They say an ancient Mayan calendar predicts the end of an era or possibly even an apocalypse.
So for our Geo Quiz we're looking for the name of a historic Mayan site on Mexico's Yucatán peninsula.
It's where people have gathered around ceremonial fires near an ancient Mayan step pyramid, blowing conch shells and generally bearing witness to what they believe is a prophetic moment.
The World checks in with journalist Franc Contreras who's at the Mayan ruins of Chichen Itza in the Mexican state of Yucatan.
He says the doomsday watch is partly a serious affair and partly a celebration.