Today's Geo Quiz takes us to central Africa.
We're looking for a country where a census is taking place.
Counting people in this country can be complicated.
It has more than 200 different ethnic groups.
And just how do you go about counting hundreds of thousands of nomadic people as they roam across the Sahara Desert?
Oh -- and what about the refugees from the neighboring Darfur region of Sudan?
No matter -- thousands of census workers have hit the road to start the count.
They're fanning out from the capital, N'Djamena (n jah MEH nah) by bus, motorbike and on foot to reach remote villages.
They face one more potential obstacle, though.
The rainy season begins soon.
That will turn many roads in the country's tropical south into impassable mud paths.
So get under an umbrella if you have to --- and try to come up with the name this country that borders Libya, Sudan and the Central African Republic.