Where in the world?
The flag of Mauritania has a green field with a thin red horizontal band at the top and bottom of the field. At the center of the field is a five-pointed yellow star above an upward facing yellow crescent.

Mauritania

Native Name: موريتانيا

Population: 4,649,660

Region: Africa

Sub Region: Western Africa

Capital: Nouakchott

Currencies: Mauritanian ouguiya

Top Level Domain: .mr

Languages: Arabic

Border Countries: AlgeriaMaliWestern SaharaSenegal