Which country was Angola a colony of until 1975?

Explanation

Angola is a country in south-central Africa with 18.5 million inhabitants, covering an area of 1,246.700 km². Around 3 million live in the capital Luanda. Angola was a Portuguese colony until 1975, when the country gained independence after a revolt that was started in 1961 by the freedom fighters MPLA. Angola was the scene of an intense civil war from 1975 to 2002. Angola is the second largest producer of oil and diamonds in Africa.