1) The assassination of Archduke Franz Ferdinand of Austria in 1914 triggered the start of World War I.

2) The Beatles hold the record for the most number-one hits on the Billboard Hot 100 chart, with 20 songs reaching the top spot.

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

4) The Renaissance period, which began in Italy in the 14th century, marked a renewed interest in art, literature, science, and philosophy.