1) The Hubble Space Telescope, launched in 1990, has provided breathtaking images of distant galaxies and deep space.

2) 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.

3) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.

4) Kimchi is a traditional Korean side dish made of fermented vegetables, primarily cabbage and radishes, seasoned with chili pepper, garlic, ginger, and other spices. It is a staple in Korean cuisine and is known for its tangy and spicy flavors. Kimchi is rich in vitamins, minerals, and probiotics, making it not only a delicious accompaniment but also a healthy addition to meals.