1) The deepest part of the ocean is the Mariana Trench, reaching a depth of about 36,070 feet (10,994 meters).

2) Kim Kardashian West is an American media personality, businesswoman, and socialite. She gained fame through reality television show "Keeping Up with the Kardashians" and has built a successful brand empire encompassing fashion, beauty, and other ventures.

3) Bats are the only mammals capable of sustained flight.

4) The Russian Revolution in 1917 resulted in the overthrow of the monarchy and the establishment of a communist government under Vladimir Lenin.