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In this section you will learn what fortified structures may look like on satellite imagery.

Fortifications are structures typically built for defence – but often secondarily as highly visual expressions of power. Examples of fortifications include castles, forts (or fortresses), and defensive walls and ditches. They are often large features and so are preserved in the landscape.

For more than 5000 years, defences have been built to protect communities and their resources against theft, attack, and warfare. We have seen examples of settlements with defensive walls around them. There are also examples of fortified buildings such as military garrisons, or castles and fortresses.

Below are two examples of fortified sites seen in satellite imagery.

Seen by satellite, Qahira castle sits on top of a steep hill, as shown by the shadow it casts onto the lower land around it. Several rings of vertical walls defend the site, and a sharply winding road with four hairpin turns leads up to it. On the innermost walls, small shadows at regular intervals reveal crenellations, while pools of water are visible in both the innermost and outermost layers of defence.
Figure 1: Qahira Castle, Yemen on Google Earth. Image © 2014 Maxar Technologies

 Seen by satellite, a rectangular compound has high walls on all sides and is accessible only by one narrow gate on each side.
Figure 2: Khan al Musalla, Iraq on Google Earth. Image © 2021 Maxar Technologies

What features stand out most clearly? How do fortified sites look different from unfortified sites? And what features do you think we should look for to help identify them with remote sensing? Tell us what you think in the Comments!
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Endangered Archaeology: Using Remote Sensing to Protect Cultural Heritage

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