1) In Norse mythology, Valhalla is a majestic hall located in Asgard, the realm of the gods. It is the afterlife destination for brave warriors who die in battle, where they are greeted by the Valkyries and engage in feasting, drinking, and preparing for the final battle of Ragnarok.

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

3) The concept of human rights advocates for the basic rights and freedoms to which all individuals are entitled, regardless of their nationality, ethnicity, religion, or other characteristics.

4) The Andes, stretching along the western coast of South America, is the longest mountain range in the world, spanning over 4,300 miles (7,000 kilometers).