1) The Amazon rainforest produces more than 20% of the world's oxygen.

2) In Norse mythology, the Valkyries are divine maidens who serve Odin, the chief god. They are responsible for selecting warriors worthy of entering Valhalla and escorting them to the afterlife. They are often depicted as powerful and beautiful figures, riding winged horses and wielding spears.

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 novel "To Kill a Mockingbird" by Harper Lee has been translated into more than 40 languages and has sold over 40 million copies worldwide.