The term MARINES' HYMN CITY is referring to the city of Tripoli, which is the capital of Libya and has seven letters. Tripoli is an ancient city that has been inhabited since the 7th century BC. It is known for its rich cultural heritage and is home to many historical sites. The Marines' Hymn, which is the official hymn of the United States Marine Corps, mentions Tripoli in its lyrics as a reference to the First Barbary War, which was fought between the US and the Barbary states in 1805.