Final answer:
Greece is the country with the Aegean Sea forming much of its eastern coast, playing a critical role in ancient history and the rise of Greek civilization.
Step-by-step explanation:
The country with the Aegean Sea forming much of its eastern coast is Greece. The Aegean Sea is significant in ancient history, lying between what is now Greece and Turkey, and encompassing over 2,000 islands with Crete being the most significant.
Historical civilizations such as the Minoans and Cycladic peoples thrived in this region, using the sea for travel, trade, and obtaining resources. The Aegean region played a pivotal role in the development of Greek civilization and culture, as it facilitated exchange of goods, ideas, and culture with neighboring regions.
The Aegean Sea's history is deeply entwined with the narratives of the ancient world and has been a cradle for various civilizations that have shaped the heritage of southern Europe.