1) The Northern Lights, also known as the Aurora Borealis, are natural light displays that occur in the polar regions due to interactions between the Earth's magnetic field and solar particles.

2) The legislative branch in many democracies is responsible for making laws, representing the interests of the people, and providing checks and balances on the executive branch.

3) The first modern health insurance policy was introduced in Germany in the late 19th century.

4) The tongue of a blue whale is so big that about 50 people could stand on it.