1) The concept of gravity was famously described by Sir Isaac Newton after an apple fell on his head.

2) The game of baseball, often referred to as "America's pastime," is played between two teams of nine players and has a rich history dating back to the 18th century.

3) The first smartphone, the IBM Simon, was introduced in 1992 and featured a touchscreen, email capabilities, and apps such as a calendar and calculator.

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