1) Sir Elton John, born Reginald Kenneth Dwight, is an English singer, songwriter, and pianist. With a career spanning over five decades, he is one of the best-selling music artists in the world and has received numerous awards and accolades for his contributions to music.

2) The Sydney Opera House, situated in Sydney, Australia, is an iconic architectural masterpiece and a UNESCO World Heritage site. Its unique design, resembling sailboats or shells, has made it one of the most recognized and photographed landmarks in the world.

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) Priyanka Chopra Jonas is an Indian actress, singer, and film producer who has made significant contributions to both Bollywood and Hollywood. She gained international fame through her role in the television series "Quantico" and has since starred in successful films.