Physical geography definitely affected the Ancient Greek civilization! Greece is a peninsula, and area of land surrounded on three sides by water. Being almost entirely surrounded by water, Ancient Greece had lots of coastline and harbors. This was important to their civilization for trade. Secondly, being surrounded by water helped the people to make a living. They had to make a living by building boats. Greece also has many mountain ranges. Mountains were important to the Ancient Greeks because they provided barriers/protection against enemies and fresh water.