Tolkien's most widely read works, The Hobbit and The Lord of the Rings, take place entirely in Middle-earth, and Middle-earth has also become a short-hand to refer to the legendarium and Tolkien's fictional take on the world.
The Two Trees of Valinor in the fictional universe of J.R.R. Tolkien's Middle-earth are Telperion and Laurelin, the Silver Tree and the Gold Tree that brought light to the Land of the Valar in ancient times. They were destroyed by Melkor and Ungoliant the great spider. Morgoth/Melkor stabbed each of the trees with his spear, and Ungoliant drank them dry. But the last flower of Telperion and the last fruit of Laurelin were made by the Valar into the Moon and the Sun.
The Old Norse name "Gandalfr" appears in the list of dwarves in the Völuspá of the Elder Edda; the name means "cane-elf". Tolkien took the name along with the dwarves' names when he wrote The Hobbit in the 1930s. He came to regret the creation of this "rabble of eddaic-named dwarves, [...] invented in an idle hour" (The Return of the Shadow:452), since it forced him to come up with an explanation of why Old Norse names should be used in Third Age Middle-earth. He solved the dilemma in 1942 by the explanation that Old Norse was a translation of the language of Dale. The figure of Gandalf has other influences from Germanic mythology, particularly Odin in his incarnation as "the Wanderer", an old man with one eye, a long white beard, a wide brimmed hat, and a staff: Tolkien states that he thinks of Gandalf as an "Odinic wanderer" in a letter of 1946 (Letters no. 107).