1) Mount Everest, located in the Himalayas, is the highest peak on Earth, with an elevation of 8,848 meters (29,029 feet). It is a popular destination for mountaineers and represents a significant challenge due to its extreme altitude and harsh weather conditions.

2) Rihanna, born Robyn Rihanna Fenty, is a Barbadian singer, actress, and businesswoman. She has achieved great success in the music industry with hits like "Umbrella," "Diamonds," and "Work," and has also ventured into the worlds of fashion and cosmetics with her brands.

3) 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).

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