Mexico City's historic square figures in today's Geo Quiz.

It's one of the world's largest and oldest public squares. Its landmarks include the Metropolitan Cathedral, and the National Palace. Our reporter there Franc Contreras says all roads lead to this central plaza:

"It's right smack dab in the middle and most metro lines will actually take you there. This is a historic plaza where protests have taken place over the centuries really and in recent times major protests we've seen millions of people cramming themselves into that plaza to protest elections, to protest against corrupt politicians, so its really the heart center of Mexican cultural and political life."

Archaeologists think they've made a big find there, the tomb of an Aztec emperor who ruled around the time that Columbus landed in the New World. So if you can, name Mexico City's historic square where Aztec history may be coming to the surface.