Short answers, pulled from the story.
Three gods fashioned the first human couple Ask and Embla from driftwood and breathed life into the wood with three distinct gifts. This creation story is preserved in the Prose Edda and the poem Völuspá.
Odin hung himself upside down on Yggdrasil for nine days and nine nights, pierced by his own spear, to discover the secrets of the runic alphabet. He sacrificed his physical perfection to pass the knowledge of the runes to humanity.
The god Týr lost his right hand to the jaws of the great wolf Fenrir during the process of binding the beast. This sacrifice highlights the theme of self-sacrifice that permeates Norse mythology.
Ragnarök is a cataclysmic event where the world is enveloped in flames and the gods face their enemies in an immense battle. The wolf Fenrir swallows Odin, the world serpent Jörmungandr rises from the sea, and the sun is devoured by the wolf Sköll.
Icelandic scholars recorded the oral traditions in the 13th century, with the Prose Edda composed by Snorri Sturluson. The Poetic Edda was also compiled anonymously in the same century to provide a more direct source of the myths.
Interest in Norse mythology surged since the 17th century when key texts attracted the attention of European intellectual circles. The Romanticist Viking revival re-awoke a fascination with the subject during this period.