Armenelos, the City of Kings, was the island nation of Númenor's capital city. The city was founded by Elros, son of Eärendil and brother of Elrond, who took the name Tar-Minyatur when he ascended the throne. As Tar-Minyatur, he oversaw the first construction of the citadel of Armenelos on a hill just to the southwest of Meneltarma in Arandor. He also oversaw the construction of the tower that became known in the city as Elros' Tower. Not far from this tower was planted Nimloth, the white tree of Númenor, symbol of the Dúnedain, and parent of the White Tree of Gondor.

Armenelos soon became the most populous and fairest city in Númenor and was generally known as Armenelos The Golden. It remained the most populous Númenorian city throughout the nation's entire existence.

Númenóreans built no places of worship but instead gave thanks to Ilúvatar from the summit of Meneltarma. However, shortly after Sauron was brought to Armenelos as a prisoner by Ar-Pharazôn he convinced the king to erect a great Temple to Melkor, "The Giver of Freedom". The completion of Sauron's Temple was celebrated by the burning of Nimloth on the Temple's altar and marked a change in Armenelos to a fearful city of smoke, fumes and human sacrifice.