Beirut is the capital and largest city of Lebanon. As of 2014, Greater Beirut has a population of 2.5 million, which makes it the fourth-largest city i…Beirut is the capital and largest city of Lebanon. As of 2014, Greater Beirut has a population of 2.5 million, which makes it the fourth-largest city in the Levant region and the sixteenth-largest in the Arab world. The city is situated on a peninsula at the midpoint of Lebanon's Mediterranean coast. Beirut has been inhabited for more than 5,000 years, making it one of the oldest cities in the world.