Greeks are the enemies of Rome. The Greeks, are located in Europe, Greece. Their capital is currently Athens. In The Heroes of Olympus series by Rick Riordan they are mostly associated with Camp Half-Blood which is located in New York for being demigod children of gods and goddess'.
In the olden days, Greeks worshipped gods, believing they were the reason for good fortune, storms, everything from arts to water. They lasted for a large amount of time, believing in the gods and living in fear from them, telling stories about them. After the golden age of the Greeks the Romans eventually came along and conquered them after some dispute.
There had been a legend, that some Greeks survived and escaped the Romans wrath. The Romans, admiring the Greeks built and empire that lasted much longer and had the Greeks' very same gods, only more warlike and militaristic. Zeus went by the name of Jupiter, Hera was Juno and etcetera.
Those Greeks went on, and founded Camp Half-Blood, located on Long Island, the only safe place (so they thought) for demigods. The Romans, when they fell, went on to make Camp Jupiter in secret, doing Jupiter's bidding and moving around to wherever the Western Civilization influence was strongest. The Romans and Greek demigods, met many times in history.
The Trojan War, for example was one. Then, there was the Civil War, World War I and World War II. Everytime, the demigods met, they fought. The gods tried to hide them from one another with the Mist, whenever they went on a quest and accidentally met and did this successfully for awhile. The camps went on without knowing about one another for a long time.
In the Second Titan War, when Saturn (Kronos in Greek aspect) tried to make a comeback at the gods, Camp Jupiter (Romans) went to their base camp and fought the Titan Krios. Jason Grace, toppled Kronos' black throne and assumed that Kronos dissapeared after that. In reality, the demigods from Camp Half-Blood (Greeks) had protected Olympus, in Manhattan. Percy Jackson, had fought Kronos and, with assistance, defeated him.
Greece is currently, is a founding member of the UN (United Nations) since 1981. Athens is the capital and largest city. The coordinates are 58 N 23'43 E. They are located at the crossroads of Europe, Asia and Africa, and has land borders with Albania.