1) The concept of 3D printing, also known as additive manufacturing, was first introduced in the 1980s and has since revolutionized prototyping and small-scale production.

2) Will Smith is an American actor, rapper, and producer known for his roles in films such as "Men in Black," "Independence Day," and "The Pursuit of Happyness." He has achieved success in both the music and film industries and has received numerous accolades for his work.

3) The highest-grossing concert tour of all time is U2's "360° Tour," which earned over $735 million in ticket sales.

4) 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).