1) The ocean covers about 71% of the Earth's surface and contains roughly 97% of the planet's water.

2) The word "yesterday" contains three vowels: E, A, and A.

3) 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.

4) The largest living structure on Earth is the Great Barrier Reef, spanning over 2,300 kilometers (1,400 miles) along the coast of Australia.