Do they still teach that the world is flat in Christian schools as well, I wonder?
flat world is an invention of XIX century "historians". The fact that the earth is a sphere has been known for thousands of years.
A reminder of a statue in Ephesus showing the round world at the feet of one of the rulers (don't remember which one)

Shinto/Buddhist temples in Japan often have two statues of lions. A female on one side a male on another. A female has her paw on a little cub, a male has it's paw on a sphere symbolizing the world.
Imperial insignia in Byzantium consisted of a scepter (symbolizing the power) and an "apple", a sphere with a cross on top of it symbolizing the world dominated by Christianity.
A (now destroyed) statue of Justinian in Constantinople, look what he holds in his left hand... a
globus crucigerWikipedia:
"The globus cruciger (Latin, "cross-bearing orb") is an orb (lat. globus) topped (lat. gerere = to wear) with a cross (lat. crux), a Christian symbol of authority used throughout the Middle Ages and even today on coins, iconography and royal regalia. It symbolises Christ's (the cross) dominion over the world (the orb), literally held in the dominion of an earthly ruler (or sometimes celestial being such as an angel). When held by Christ himself, the subject is known in the iconography of Western art as Salvator Mundi ("Saviour of the World"). It is associated with the sceptre."
http://en.wikipedia.org/wiki/Column_of_Justinian