1) 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.

2) The Machu Picchu archaeological site, located in Peru, is an ancient Incan citadel situated high in the Andes Mountains. It is recognized as a UNESCO World Heritage site and attracts visitors from around the world who come to marvel at its remarkable architecture and scenic surroundings.

3) The world's first insurance policy was issued in 1347 in Genoa, Italy. It insured against the risk of maritime trade.

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