1) The Brexit process, initiated by the United Kingdom's referendum in 2016, led to the country's withdrawal from the European Union in 2020, marking a significant political and economic change for both the UK and the EU.

2) The coldest known temperature in the universe was achieved in a laboratory in 2019, reaching a fraction of a degree above absolute zero (-273.15 degrees Celsius).

3) The concept of political parties allows for organized groups to mobilize support, articulate policy positions, and compete for political power through elections and political campaigns.

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.