1) The first successful portable MP3 player, the Diamond Rio PMP300, was released in 1998 and could hold up to 60 minutes of music.

2) The Age of Exploration, during the 15th and 16th centuries, saw European explorers such as Christopher Columbus and Vasco da Gama reach new lands and establish trade routes.

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

4) The Southern Ocean surrounds Antarctica and is the coldest and least-visited ocean.