1) The musical "The Phantom of the Opera" has been running in London's West End since 1986, making it the longest-running musical in history.

2) Insurance fraud occurs when individuals or organizations deliberately deceive insurance companies to receive undeserved benefits.

3) The smallest unit of time is known as a zeptosecond, which is equal to one trillionth of one billionth of a second.

4) The Sahara Desert, located in North Africa, is the largest hot desert in the world, covering an area of about 9.2 million square kilometers (3.6 million square miles). It is characterized by vast stretches of sand dunes, rocky plateaus, and extreme temperatures.