1) The word "guitar" contains three vowels: U, A, and I.

2) The concept of sovereignty refers to the supreme authority and power of a state to govern itself, make decisions, and control its own territory without interference from external forces.

3) The Treaty of Versailles, signed in 1919, officially ended World War I and imposed heavy penalties and reparations on Germany.

4) The longest English word is "pneumonoultramicroscopicsilicovolcanoconiosis," which refers to a lung disease caused by inhaling very fine silica dust.