1) The Mariana Trench in the western Pacific Ocean is the deepest part of the world's oceans, reaching a depth of approximately 36,070 feet (10,994 meters).

2) The naming of cyclones varies depending on the region. For example, cyclones in the Atlantic and eastern Pacific Ocean are named using a predetermined list of names.

3) The blue whale is the largest animal to have ever existed, with an average length of about 82 feet (25 meters).

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.