Troy (Latin Ilium) was an ancient city in Eurasia on Earth.
In his epic poem Iliad, the ancient Greek author Homer wrote about the siege of this city by the Greeks in about 1200 BC. Upon seeing Yeoman Teresa Ross, Trelane remarked on her beauty inquiring if hers was "the face that launched a thousand ships and burnt the topless towers of Ilium?" (TOS: "The Squire of Gothos")
The city was rediscovered in the 1870s by the German archaeologist Heinrich Schliemann. According to Galen, this discovery counts among the greatest archaeological discoveries of all time. (TNG: "The Chase")
Henry Janeway compared himself to Hector slipping past the Greek lines and bringing supplies to the "embattled city of Troy", when he brought supplies to his store Alexandria Books in late 2000. (VOY: "11:59")