Much of Greece is mountainous and rocky terrain, with the occasional plain. The Pindus Mountains start in northern Greece and stretch south to the Gulf of Patra. In the southern part of Greece are the Peloponnesus Mountains. About 20% of Greece is made up of thousands of islands in the Ionian Sea to the west, the Aegean Sea to the east and the Mediterranean Sea to the south.
Whales, dolphins, seals, sea turtles and numerous fish species are found within Greek waters. On land, small populations of bear wolf, wildcat, jackal and chamois are still found in sparsely populated areas.
Greece’s main environmental problems are industrial smog and automobile exhaust fumes in Athens; over half of all industry is located in the greater Athens area. Marine and freshwater pollution are a significant problem due to industrial pollutants and agricultural run-off such as fertilizers, pesticides and sewage. Overfishing and deforestation are other issues threatening Greece’s environment.