1) The ozone layer, located in the Earth's stratosphere, protects us from harmful ultraviolet (UV) radiation.

2) The world's first credit card was introduced in 1950 by Diners Club.

3) The first commercial mobile phone, the Motorola DynaTAC 8000X, was released in 1983 and weighed nearly 2 pounds.

4) The Hollywood Walk of Fame features more than 2,690 stars embedded in the sidewalk, honoring notable figures in the entertainment industry.