1. Ironworking probably spread to the rest of Africa via the Meroitic civilization.
2. Finely ground pigments mixed with a base such as egg yolk was the exclusive medium for painting panels in the Middle Ages.
3. Trade relations between Egypt and Africa began in 1460 BCE when Queen Hatshepsut sent her ships to the country of Punt, today's Somalia.
4. The Freedom of Information Act, passed by the U.S. Congress in 1966, gives U.S. citizens the right of access to public records.
5. In the Sonoran Desert, the daytime temperatures rise to 50 degrees Celsius.