1) The word "island" contains two vowels: I and A.

2) The NBA (National Basketball Association) is widely regarded as one of the most popular and competitive professional basketball leagues in the world.

3) 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.

4) The Federal Reserve System, often referred to as the Fed, is the central banking system of the United States.