Greece is an amazing country that can't be seen in just one trip. The is partly because it is a country with so much history, but also because a large portion of the country is made up of islands, sprinkled along the coasts, and spilling out into the Mediterranean and Aegean Seas. The capital city of Athens is located in the southeast of the mainland, the ancient city of Olympia is located in the west in the Pelopnnese, but other major destinations are islands. There is the island of Crete, Mykonos which is located in the Cyclades islands, Rhodes in the Dodecanese islands, which is actually closer to Turkey, and the wonderfully quaint island of Corfu, located in the northwest, near Albania.
It is a wonderful destination for tourists and travelers, because tourism is a major industry, many shop and restaurant owners speak English, but learning a few Greek words will certainly earn you some points. Most of the people are extremely helpful, and willing to assist. In the islands, the water is the deep and brilliant blue that you picture, and everywhere you turn there is more history than you can absorb.