1) The Rocky Mountains, also known as the Rockies, extend from Canada through the United States, offering stunning landscapes and outdoor recreational opportunities.

2) The Amazon rainforest produces more than 20% of the world's oxygen.

3) The United Nations (UN) is an international organization founded in 1945 with the goal of promoting peace, security, and cooperation among nations through diplomatic and political means.

4) 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.