Mecca
The Kaaba is Islam's holiest building located in the city of Mecca. It now stands some 60 feet high and each side is approximately 60 feet in length. Most Muslims travel to see it at least once in their lifetime on a journey called The Hajj. They believe that it was built by Abraham.
Medina
Medina is where Muhammad was exiled after he found little support for his ideas in his home city of Mecca.