1) The first commercially successful video game was "Pong," released in 1972 by Atari.

2) The ocean is home to an incredible variety of marine life, including thousands of species of fish, mammals, reptiles, and invertebrates.

3) 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.

4) The United States operates under a two-party system, with the Democratic Party and the Republican Party being the two major political parties that compete in elections and shape the country's political landscape.