1) The speed of light is approximately 299,792,458 meters per second.

2) The first consumer digital video recorder (DVR), the TiVo, was introduced in 1999 and allowed users to record and store television programs for later viewing.

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

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.