1) The development of artificial intelligence (AI) has led to advancements in areas such as machine learning, natural language processing, and computer vision.

2) 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.

3) The World Wide Web, developed by Tim Berners-Lee in 1989, revolutionized the way information is accessed and shared on the internet.

4) The world's largest volcano, Mauna Loa in Hawaii, is also one of the most active. It stands over 13,000 feet (4,000 meters) above sea level.