Greece is a small country towards the east of the Mediterranean Sea. It is made of a peninsular and many islands. This is called an archipelago.
Greece has a Mediterranean climate, with hot, dry summers and cool, often rainy winters.
It is a mountainous country, so that each part of the country is cut off from the others either by mountain ranges or water or both. That is one reason the Ancient Greeks developed separate city states, rather than uniting as a country as the Egyptians did. Each city state developed around an area of fertile valley land. This land was good enough to feed the population at the beginning, but as populations rose, so there was difficulty getting enough food. This caused Athens to look for food overseas, which resulted in their developing shipbuilding and trade.
By contrast, places like Sparta were in poor agricultural country, and Sparta was far from the sea. So the only way they could see of getting more food was to capture other lands, and this is one reason they developed an army.
The Ancient Greek city states eventually fought themselves to a standstill. After this a single king ruled. At first it was the king of Macedonia, and then it was his son, who went on to become Alexander the Great.
But the Greek empire that developed around Alexander needed a powerful ruler, and when Alexander was killed, the empire began to collapse, and was eventually taken over by the Romans.
After this, Greece was never powerful again. Modern Greece still relies partly on selling farming products like Feta cheese and olives, and on shipbuilding, both very ancient ways of life. But it is very dependent on tourists coming to see its ancient ruins and stay in hotels by its sunny beaches.