In J. R. R. Tolkien's legendarium, the history of Arda, also called the history of Middle-earth, began when the Ainur entered Arda, following the creation events in the Ainulindalë and long ages of la
Tolkien meant Arda to be what Paul H. Kocher calls "our own green and solid Earth", seen here in the Baltistan mountains, "at some quite remote epoch in the past".
Tolkien likened the Last Battle, Dagor Dagorath, that ends "the world" (Arda) to the Norse Ragnarök. Engraving Battle of the Doomed Gods by Friedrich Wilhelm Heine, 1882
Sketch of one of Tolkien's conceptions of Arda within the Void, Kúma, showing the Encircling Ocean, Ekkaia around the Flat Earth, Ambar, the Air, Vista, and the Starry Heaven, Ilmen, before the creation of Sun and Moon.