One of the oldest and easiest ways to find a place is by using a map. We have been making maps throughout our history. I'm sure one of the first maps were sketched in the sand. Today we have maps on our cells phones.
In Mesopotamia maps were drawn on clay tablets. One of the oldest maps is from about 2500 BCE. The Mesopotamia map included their towns and country and what they considered the whole world. Check out more clay tablets at Babylonian Tablets.
Even though we know that the earth is a sphere it was not proved until Magellan finished his expedition by sailing around the world in the 16th century.
The geometry of the earth's shape has made it possible to plot the earth in degrees.When you cut the earth in two halves it forms circles. The circle is divided into 360 parts or degrees. The earth is divided into degrees going north and south, east and west. The lines that go east to west are called parallels. The north to south lines are called meridians. This means that parallels never intersect with each other but meridians intersect at the poles, or the bottom or the top of a sphere.
Here is a printout about longitude and latitude.