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

2) The Boston Celtics and the Los Angeles Lakers are the most successful teams in NBA history, with a combined total of 33 championships.

3) The world's oldest known living tree is a bristlecone pine named "Methuselah" in California, estimated to be over 4,800 years old.

4) 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.