A fort differs from both castles and palaces in that it is a military fortification rather than a home. These constructions were designed with battle in mind and are used to protect certain territory. Castles, on the other hand, were primarily built for defense but also served as royal residences. They tend to be larger than forts and usually have more complex systems of defense including walls, towers, and gates. Palaces were luxurious homes for royalty or nobility. Often constructed out of stone, they could be large enough to house entire families. Although they were rarely used as defensive structures, some examples do exist today. For example, The Palace of Versailles was never actually attacked but was completely destroyed during the French Revolution. Now you know! Fortification techniques improved over time and different cultures came up with different solutions for building these defenses. For example, early Chinese armies used earthworks for protection while European armies used metal weapons which could destroy such defenses easily.