1) 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.

2) The first successful mass-produced personal computer, the IBM PC, was introduced in 1981 and played a significant role in popularizing the use of computers in homes and offices.

3) The name "Bluetooth" comes from the 10th-century Danish king, Harald Bluetooth, who united Denmark and Norway.

4) The Serengeti National Park, located in Tanzania and extending into Kenya, is renowned for its vast savannahs, diverse wildlife, and the annual wildebeest migration. It is a UNESCO World Heritage site and a popular destination for safari enthusiasts and nature lovers.