1) The Mona Lisa, painted by Leonardo da Vinci, is one of the most famous and valuable artworks in the world.

2) In Norse mythology, the World Tree, known as Yggdrasil, is a massive ash tree that connects the nine realms of existence. It is considered the center of the cosmos and serves as a conduit between different realms, including Asgard (realm of the gods), Midgard (realm of humans), and Helheim (realm of the dead).

3) The Southern Ocean surrounds Antarctica and is the coldest and least-visited ocean.

4) The highest mountain in Africa is Mount Kilimanjaro, standing at 19,341 feet (5,895 meters) tall.