Where in the world?
The flag of Qatar has a maroon field with a broad white serrated band (nine white points) on the hoist side.

Qatar

قطر

Population: 2,881,060

Region: Asia

Subregion: Western Asia

Capital: Doha

Top Level Domain: .qa

Currencies: Qatari riyal

Border countries

The flag of Saudi Arabia has a green field with white Arabic inscription and a sword.

Saudi Arabia

Population: 34,813,867

Region: Asia

Capital: Riyadh