Nauru is officially called the Republic of Nauru, and is just one island. It has a total area of 21 sq km and a population of 9,378. It is the second smallest nation by population in the world. It is a phosphate rock island, which allowed profitable strip mining until 2011, when it became no longer viable for extraction. It was first inhabited in 1000 BCE, and was annexed by Germany in 1888, and became independent in 1968.