1) The COVID-19 pandemic has highlighted the importance of global collaboration and solidarity in addressing public health emergencies, with efforts focused on vaccine sharing, equitable distribution, and support for developing countries.

2) The Great Barrier Reef in Australia is the largest coral reef system in the world and is visible from space.

3) 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.

4) Leonardo DiCaprio is an acclaimed American actor and environmental activist. He has starred in numerous successful films, including "Titanic," "The Revenant," and "The Wolf of Wall Street," and has been recognized with several awards, including an Academy Award.