1) The world's oldest living plant is believed to be a clonal shrub called "Old Tjikko" in Sweden, estimated to be over 9,500 years old.

2) Banks play a vital role in the economy by facilitating the flow of funds between savers and borrowers, providing loans, and offering various financial services.

3) The United Nations Security Council is responsible for maintaining international peace and security, with five permanent members (China, France, Russia, the United Kingdom, and the United States) holding veto power over resolutions.

4) In Norse mythology, Ragnarok is a cataclysmic event that signifies the end of the world. It involves a series of apocalyptic battles and natural disasters, leading to the destruction of the gods and the world as it is known. From the ashes, a new world and a new generation of gods emerge.