The Minoan Civilization:
The Minoan civilization was located on the island of Crete. Their focus was on trade, not war so they had a strong economy, they traded with Egypt and Mesopotamia. They didn't have fertile soil so all they could trade were Holland olives and wine. In return they were given spice, silk, and papyrus.
This civilization reached its golden age between the years 1750 B.C.E. and 1500 B.C.E.
The most famous place was the palace at Knossos. It had beautiful art, golden statues, a banquet hall, and bedrooms for the royal family.
This civilization disappeared around 1400 B.C.E.
The Mycenaen Civilization:
The Mycenaens dominated the Aegean world between 1400-1200 B.C.E. They were even better sea traders than the Minoans; they traded to Sicily, Italy, Egypt, and Mesopotamia. Each Mycenaen city lived in a separate walled fort. Wealthy rulers made hordes of treasure.
The Mycenaens took part in the Trojan War, which took place in 1250 B.C.E.
This is the main reason they were remembered and also was their greatest accomplishment.
The Hellenic Civilization:
The Hellenic Civilization was founded by a man named Zeno, taught his people that they were all morally equal and to accept whatever life brought to them.
The Hellenics also invented what is today geometry, the equaison (a2+b2=c2) this is the formula to calculate the relationship between the sides of a right triangle. This was, in fact their greatest accomplishment since without them we wouldn't be able to make buildings, we would be missing loads of education, socity just wouldn't be the same.