1) Sourdough bread is a type of bread made through a fermentation process that involves wild yeast and lactic acid bacteria. It has a distinct tangy flavor and a chewy texture. Sourdough bread is often considered healthier than conventional bread due to its potential benefits for digestion and nutrient absorption. It has gained popularity in recent years, with artisanal bakeries and home bakers reviving the traditional art of sourdough baking.

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

3) In Greek mythology, the Trojan War is a legendary conflict between the city of Troy and the Greeks, sparked by the abduction of Helen of Troy. It is immortalized in Homer's epic poems, the Iliad and the Odyssey, and features famous heroes like Achilles, Hector, and Odysseus.

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