1) The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered the start of World War I.

2) The word "music" contains two vowels: U and I.

3) The Earth's core is primarily composed of iron and nickel and is as hot as the surface of the sun.

4) The concept of insurance dates back to ancient times when merchants would distribute their goods across different ships to reduce the risk of losing everything in a single event.