1) The concept of augmented reality (AR) involves overlaying digital information and virtual objects onto the real world, enhancing the user's perception and interaction with the environment.

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

3) The ancient city of Pompeii was preserved under layers of volcanic ash after the eruption of Mount Vesuvius in 79 AD, providing valuable insights into Roman life.

4) The Nile River, spanning approximately 6,650 kilometers (4,130 miles), is the longest river in the world. It flows through eleven countries in northeastern Africa, supporting various civilizations throughout history and serving as a vital source of water and transportation.