1) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.

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 world's largest diamond, the Cullinan, was discovered in South Africa in 1905 and weighed over 3,000 carats.

4) The first computer mouse was invented by Douglas Engelbart in 1964 and consisted of a wooden shell and two metal wheels.