1) In Norse mythology, the Valkyries are divine maidens who serve Odin, the chief god. They are responsible for selecting warriors worthy of entering Valhalla and escorting them to the afterlife. They are often depicted as powerful and beautiful figures, riding winged horses and wielding spears.

2) The invention of the printing press by Johannes Gutenberg in the 15th century revolutionized the spread of knowledge and played a key role in the Renaissance.

3) The recent advancements in space exploration include missions to Mars by various space agencies, such as NASA's Perseverance rover landing on Mars in 2021, aiming to explore the planet's geology and search for signs of past microbial life.

4) The sport of golf originated in Scotland and is played on courses with 18 holes, each with a designated par score.