1) The invention of the printing press by Johannes Gutenberg in the 15th century revolutionized the spread of knowledge and played a key role in the Renaissance.

2) In African mythology, there is a rich tapestry of diverse beliefs and stories across the continent's many regions and cultures. It includes deities, spirits, and mythical creatures, with narratives often addressing themes of creation, ancestral heritage, and the forces of nature.

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

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).