Aerial archaeology studies the remains from above. This technique enables a better and different understanding from the ground study. Either it is made from hot air balloons, scaffolds, airplanes, or cameras attached to kites. Since the First and Second World War, archaeologists gained access to this technique once with the inception of aerial photography. Vertical and oblique or angled pictures are the basis of scaled plans or a three dimensional effect. New technologies made possible for sites to be stereoscopically viewed and reconstructed, after a pair of vertical and angled pictures are overlapped.
Aerial archaeology is the most important tool for the discovery of new sites. There are a few signs that give the probability of an ancient settlement. These are:
- Shadow marks, which are slight differences in the ground levels, that are seen from airplanes when the sun is low and casts long shadows.
- Cropmarks or buried ditches, that are visible after the rainy season, as they tend to hold more water, or buried walls, that hold less water. These signs are visible also in the quality of the crops that exist on the site, as they will grow taller or shorter, depending on the kind of ground they are planted on.
- Frost marks, appear in winter on ploughed fields. They are recognised by the amount of water accumulated on certain areas.
- Soil marks are differences on the color of the soil. They appear between natural and archaeological deposits.
The famous Nazca lines from Peru are the best example for this category. The lines from the soil have no special meaning, but are easily recognizable from the air. Specialists believe they were created by the Nazca culture, which lived between 500 BC and 500 AD. More than 70 designs with birds, llamas, jaguars, monkey, fish, humans, trees and flowers are spread on the arid plateau between the towns of Palpa and Nazca. The stable climate preserved the ground shallow marks dug into the reddish pebbles, that revealed the grayish ground beneath.