Castles were frequently erected on the summits of hills or where natural characteristics of the terrain could be used to aid in defense. The British Isles have a long history of castle building and many castles can be found across Europe and Asia as well.
The first true castles began to appear around AD 1000 in Europe. Soldiers from the emerging kingdoms of Germany and France constructed defensive towers on hilltops to protect themselves from invasion by larger nations like England, Italy, and Spain. They were able to do this by capturing prisoners of war and extracting money from them with what we know today as "slave labor." The Germans called these soldiers "Ritter" which translates to "knight"; thus, knights were originally defenders of castles who fought for land owners (often royalty) in order to be granted land for themselves and their families.
Over time, these early castles grew in size and strength until they became military centers where troops could be housed, supplied, and commanded in times of war. In addition, new technologies were developed over the course of several centuries that allowed for the construction of more sophisticated castles. These include gunpowder, mortar fire, and tanks on modern battlefields.
Castles were not erected as often after the Middle Ages, owing to the development of heavier weapons and cannons that could easily take down their walls. However, a number of these medieval ruins can still be seen across Europe.
There are several reasons why people built castles on hillsides or islands. One reason is that it made defence easier because an enemy approaching from any one direction would have been exposed. Also, if someone was attacking your castle from the rear or the side, they would not be able to fire arrows or crossbow bolts at you while avoiding being hit themselves. Last but not least, the presence of a castle on a hill made it visible over a large area, which meant that threats might have been reported sooner than otherwise possible.
With modern technology, most people would assume that defences would be based on guns or other weapons that could shoot far enough to reach attackers coming from a distance. But this is not always the case: some castles were actually designed to look like giant birds' nests with their high sides and deep ditches. These castles were called "birds' nests" because it was believed that such arrangements would offer better protection than more conventional structures.
People also built castles on hills for aesthetic reasons. They wanted their homes to be impressive to see.
Castles were erected in strategic locations, and natural fortifications like as hills, rocky outcrops, and rivers were used wherever practical. A castle on a hill is the ideal location. The higher a castle is located, the greater its defensive advantage. However, a fortress cannot exist without a well; otherwise, the adversary may poison your water supply. Therefore, you need clear ground around the base of the hill for hundreds of feet in all directions.
Castles were also built under bridges or in caves. If possible, the owner wanted to make sure that no enemy could enter his territory from the outside. He would block up any holes or cracks with stone or dirt.
In conclusion, castles were built anywhere there was an opportunity for improvement over the open land defense system. Most sites were chosen because they were already high points overlooking important roads or cities.
Many castles exploit natural characteristics of the area in which they are built to strengthen their defensive capabilities; some are built on lakes and islands, while others use rivers as moats. Some are built on hills, which provides protection from enemy missiles being thrown at them.
Castles on cliffs allow defenders to attack enemies approaching their gates from above. They can also be attacked from below by warriors climbing the cliff faces with little risk of being shot by archers who guard the walls.
In addition, defenders can see far away into neighboring towns or villages, looking for an opportunity to strike back at their attackers.
Cliffs provide plenty of space for soldiers to engage in battle, so they're often chosen as sites for military camps or fortresses.
Some castles were built without any intention of defending themselves against attacks by armed forces; they were designed only to keep out thieves and other criminals who might want to take advantage of their occupants' wealth. These are called "thief's castles" or "rogue's towers."
But most castles were built to defend settlements against invasion by armies led by kings or other powerful people.