In the days before electricity, blocks of lime were heated until they glowed in order to produce light on stage. Thus, actors and actresses "basked in the limelight".

All mammals have 7 neck vertebrae.

The lighter was invented before the match.

It takes sloths 2 weeks to digest their food.

The toothbrush was invented in 1498.

Scissors were invented by Leonardo Da Vinci.

Albert Einstein won a Nobel Prize for his work on brownian motion, but never received a Nobel Prize for his theory of relativity.

Icebergs are composed of fresh water, not salt water.

Mauna Loa is the world's largest volcano.