1) The discovery of the Americas by Christopher Columbus in 1492 opened up new trade routes and had a profound impact on world history.

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

3) The Great Barrier Reef in Australia is the largest living structure on Earth and can be seen from space.

4) The Pacific Ocean is the largest ocean on Earth, covering more than 30% of the planet's surface.