1) The word "bank" comes from the Italian word "banco," which means bench. In medieval Italy, bankers conducted their business on benches in the marketplace.

2) 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.

3) The oldest known musical instrument is a flute made from a bird bone, estimated to be around 43,000 years old.

4) The President of the United States serves as the head of state and the head of government, responsible for leading the executive branch and representing the nation domestically and internationally.