1) In Norse mythology, Valhalla is a majestic hall located in Asgard, the realm of the gods. It is the afterlife destination for brave warriors who die in battle, where they are greeted by the Valkyries and engage in feasting, drinking, and preparing for the final battle of Ragnarok.

2) Norse mythology, originating from the Scandinavian region, features gods and mythical creatures like Odin, Thor, Loki, and Valkyries. It explores themes of heroism, destiny, and the battle between gods and giants, with intricate tales recorded in texts such as the Prose Edda and Poetic Edda.

3) The Dow Jones Industrial Average (DJIA) is a stock market index that tracks the performance of 30 large, publicly owned companies in the United States.

4) The world's first insurance policy was issued in 1347 in Genoa, Italy. It insured against the risk of maritime trade.