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

2) The first modern Olympic marathon race was held at the 1896 Olympics in Athens and has since become one of the most iconic and challenging events in athletics.

3) Egyptian mythology centers around deities such as Ra, Osiris, Isis, Horus, and Anubis. It explores concepts of creation, death, and the afterlife, with elaborate rituals and beliefs shaping ancient Egyptian society. The mythology is richly depicted in temple reliefs, burial sites, and hieroglyphic texts.

4) The ongoing conflict in Syria, which began in 2011, has resulted in a humanitarian crisis, displacement of millions of people, and international efforts to bring about a resolution and provide aid to those affected.