1) The fastest recorded serve in tennis was achieved by Sam Groth at 163.7 miles per hour (263.4 kilometers per hour) during a tournament in 2012.

2) Mountains are important water sources, as they capture and store precipitation, feeding rivers and supporting ecosystems downstream.

3) The construction of the Great Wall of China began in the 7th century BC and was completed over several centuries, spanning thousands of miles.

4) The ancient Egyptian civilization, with its impressive pyramids, pharaohs, and hieroglyphics, flourished along the Nile River for thousands of years.