One of the most characteristic morphological features of the Greek peninsula is its horizontal dismemberment, with the enormous length and the astonishing variety of forms in the coastline. Greece, with a total surface of 131.957 km2 and a coastline longer than 15.000 km, has the most extensive coastline comparing to the other Mediterranean countries. The diversity of coasts is directly related to the geological history of the Greek region and particularly with the processes that are related with the breaking and the immersion of Aegiis during the last 2 million years. During this time, the land was split and, depending on the local conditions, some parts arose in comparison to the neighbouring parts (horst) and others sunk (trench). The low altitude areas flooded and they shaped gulfs and channels, while the high altitude areas remained out of the seawater and together with the tops of the old mountains of the Aegiis shaped the capes, coastal hills and islands. The final form of the coastline however was also influenced by the total emertion of big parts of Greece (Peloponnese, Crete), which took place in the last 1 million years, reshaping the coastline.
A special phenomenon is the rising of the sea level, which is related to the global warming and with the fusion of glaciers. It has been calculated that 18.000 years ago the level of Greek seas was more or less 100 m lower than today.
The phenomena that took place in such a great extend cannot be described as one, because the factors that influenced the area differed from region to region.
The study however of the map of Greece allows the observer to distinguish the processes that shaped the coastline in each area.
From geomorphological point of view the Aegean constitutes a relatively shallow sea, as it emanates from the sinking of Aegiis. The seabed however is corrugated by a lot of trenches, some points of which are very deep. The islands of the Aegean could be divided in seven groups: The islands of Thracian sea, the islands of Eastern Aegean, the Nothern Sporades, the Cyclades, the islands of Argosaronikos, Dodecanese and Crete. Many of the islands of the Aegean constitute in reality the extension of mainland Greece's mountains, like the Cyclades, whichhave a total surface of 2.528 km2 and are actually the tops of the mountains that have been submerged.
The Aegean has a complex coastline which leads to the formation of many small and large gulfs, capes and natural harbours. The most important gulfs are Argolikos, Limiras of Epidaurus, Ermionida sea (between Argolida and Spetses), Saronikos in Attica, Maliakos in Sterea Ellada, the Euboean gulf between Euboea and Sterea Hellas, Pagasitikos in Thessaly, Thermaikos, Torronaios, Siggitikos, Strymonikos and Kavala in Macedonia, Adramyttinos, Smyrnaikos, Efessos, Iasikos and Symi in Asia Minor, Apokoronou, Souda, Chanias, Kissamos and Mirampelou in Crete, Kalloni and Geras in Lesvos.
The main capes that have been formed are: Maleas in the peninsula of Epidaurus Limiras of Peloponnese, Skyllaio in the Argolid peninsula, Trikeri (Aianteion) in the peninsula of Pilion, Paliouri in the peninsula of Pallini Chalkidiki, Drepano in the peninsula of Sithonia Chalkidiki, Aghios Georgios or (Nymfaion) in the peninsula of Mount Athos (Athos), Elli in the peninsula Kallipolis Thrace. In Asia Minor: Karampournou, Bianko, Kanapita (Trogylion) in Mykali, Aloupo in Halicarnassus et.al.
There are a lot of harbours and ports in the Aegean. The channels that have been formed are of particular importance. The most important are the channels between Poros and Troizinia, Chalcis, known as strait of Euripos, the uniqueness of which rendered the name Euripos as an international term that characterizes similar formations, the exceptional wavy channel of Kafireas, between the south-eastern coast of Euboea and the north-western coast of Andros. Other channels are the channels of Mouzelim, between the southern coast of Troad and the northern coast of Lesvos in Adramyttino gulf, the channel between Samos and the coast of Asia Minor and the two channels that are shaped between the islands of Kos and Symi with the coastline of Asia Minor.
3. The Islands
The Aegean islands, including skerries, are thousands; a few of them however are of a considerable size. With the exception of Crete and Euboia, only Lesvos and Rhodes have a surface of more than 1.000 km2, while Chios’ surface is 841 km2.
Due to the large number of islands and the variety in their extent, the islands of the Aegean present great differences in their relief. Their geological history played an important role in this of course, as in the Aegean the geological factors acted in various ways depending on the region. The highest peaks in the Aegean are in Crete at the mountains of Psiloritis or Ithi with an elevation that reaches 2.456 m., the Leuka Ori with 2.452 m., Lasithi mountain with 2.148 m. and Kedros mountain with 1.777 m. The big mountains in Crete are the continuation of the mountain ranges of mainland Greece and cover the central and southern part of the islands’ territory from west to east. Nevertheless, they constitute a single mountain range with great length, which for practical reasons is separated from the geographers in three mountainous masses, Leuka Ori in the west, Psiloritis in the centre and Lasithiotika mountains in the east. The highest elevation of the rest of the Aegean islands is at the top Feggari (1.611 m.) of Saos mountain in Samothrace, which characterizes also the terrain of the island. Other peaks with an altitude more than 1.000 m. are found in many other islands (Chios, Naxos, Samos, Karpathos, et. al.).
There are also differences in the lowlands. In certain islands (Lesvos, Naxos) they are important, while in others (Chios, Samos) they are limited. Most of the small islands are of small to medium height. In addition, they are very irregular concerning the formation of the terrain, forcing their residents to seek resources of life in stock-raising and the sea.
Finally, a small reference to the rivers that are poured to the Aegean should be made. The main rivers are Inachos (Argolid), Pinios (Thessaly), Aliakmon, Loudias, Axios, Strimon (Macedonia), Nestos, Evros (Thrace), Caicus, Ermos, Maeander (Asia Minor) et al.