1) 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.

2) 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.

3) The invention of the printing press by Johannes Gutenberg in the 15th century revolutionized the spread of knowledge and played a key role in the Renaissance.

4) The Mariana Trench in the western Pacific Ocean is the deepest part of the world's oceans, reaching a depth of approximately 36,070 feet (10,994 meters).