1) The Dow Jones Industrial Average (DJIA) is a stock market index that tracks the performance of 30 large, publicly owned companies in the United States.

2) The Eiffel Tower can be 15 cm taller during the summer due to thermal expansion.

3) Cristiano Ronaldo is a Portuguese professional soccer player widely regarded as one of the greatest footballers of all time. He has won numerous awards, including multiple FIFA Ballon d'Or titles, and has played for top clubs such as Manchester United, Real Madrid, and Juventus.

4) The Mona Lisa, painted by Leonardo da Vinci, is one of the most famous and valuable artworks in the world.