1) Greek mythology includes a wide array of gods and goddesses, such as Zeus, Poseidon, Athena, Aphrodite, and Apollo. These deities were believed to govern various aspects of life and the natural world and were often depicted with human characteristics and engaging in dramatic stories and conflicts.

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 Olympic motto is "Citius, Altius, Fortius," which is Latin for "Faster, Higher, Stronger."

4) The world's first car radio was invented in 1929.