The advent of gunpowder revolutionised siege warfare. Before gunpowder, fortifications were designed to be tall and thin to repel attackers with archers and projectiles from heights. However, with the invention of cannons and gunpowder artillery, these tall walls became vulnerable to bombardment. As a result, fortification designs evolved. Walls became thicker, shorter, and angled, designed to deflect or absorb cannon fire rather than merely stand tall. Star forts with angular bastions emerged, allowing defenders to create crossfires against approaching assailants. Thus, gunpowder ushered in a new era where siege warfare wasn't just about outlasting a blockade but actively defending against explosive firepower.

The late 19th and 20th centuries witnessed rapid advancements in communication technologies, including the telegraph, radio, and eventually, satellite communications. Prior to these innovations, command structures in warfare were often decentralised out of necessity, as information flow was slow. Commanders in the field made decisions based on limited and possibly outdated data. With faster communication tools, higher echelons of command could relay real-time decisions, ensuring coordination across vast distances. This centralisation permitted more synchronised strategies, rapid response to changing scenarios, and better resource management. However, it also brought challenges, as the potential for micro-management from distant headquarters could impede a field commander's judgment and flexibility.

The introduction of aircraft added an entirely new dimension to warfare. Initially, planes were used for reconnaissance, providing real-time intelligence about enemy positions and movements. This aerial intelligence made outdated static defences, like forts, less viable. As aircraft technology advanced, bombing became a strategy, challenging traditional concepts of frontlines, as rear echelons and even civilian centres became direct targets. Ground forces had to adapt with anti-aircraft weaponry and altered tactics to mitigate aerial threats. The combination of ground and air assaults necessitated integrated air-ground strategies, emphasising coordination between infantry, armour, and air units. Ultimately, the addition of aircraft expanded the theatre of war and reshaped strategies, making warfare more complex and multi-dimensional.

The phalanx formation was predominantly a product of Greek military thinking, especially favoured by city-states like Sparta. It was a dense, rectangular formation, with soldiers holding long spears (sarissas) and shields (hoplons), presenting an impenetrable wall of weaponry. The key strength of the phalanx was its cohesion and mutual protection: the shield of one man protected himself and his neighbour. The formation was especially effective in narrow battlefields where the phalanx's flanks were secure. Its dominance influenced adversaries, leading to similar adaptations, such as the Macedonian phalanx, which expanded upon the original concept with longer spears and tighter formations. The phalanx's legacy continued as it informed many subsequent military strategies, emphasising coordination and collective strength.

The transition from sail to steam radically transformed naval warfare. Sail-powered ships were at the mercy of the wind and weather, which often dictated tactics, manoeuvrability, and engagement ranges. The introduction of steam power brought about independence from wind patterns, offering captains unprecedented control. This transition allowed for more direct engagements, the ability to chase down or retreat from adversaries effectively, and the flexibility to alter battle plans in real-time. Additionally, steam-powered ships could be armoured heavily without being overly concerned about weight affecting sail efficiency. The result was the emergence of ironclad warships, which dominated wooden sailing fleets and ushered in a new era of naval tactics focused on firepower and protection.