1) The Appalachian Mountains, running along the eastern coast of the United States, are one of the oldest mountain ranges in the world.

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

3) The world's largest particle accelerator, the Large Hadron Collider, is located near Geneva, Switzerland, and spans a circumference of 17 miles (27 kilometers).

4) The abolition of slavery in the United States was officially proclaimed with the ratification of the 13th Amendment to the Constitution in 1865.