Even in an era of combat aircraft, tanks, and an endless array of technological advances, the US Army still trains troops in the tactics of trench warfare. And sometimes they go to Poland to do it.

It may sound archaic, but the truth is that while trench warfare – and the horrors that go along with it – are more closely identified with , the practice has continued throughout the last century.

During WWII, Russia was well known for its use of trench warfare as a defensive measure. The outcome of the, in particular, was partially a result of Russia's extremely elaborate maze of trenches and defensive fortifications. In the Pacific, the Japanese used a series of intricate entrenchments, tunnels, and underground bunkers in an attempt to fortify the many islands it held. When the invasion did come, the trench complexes were a bane to US forces, resulting in some of the most fierce close-quarters fighting of the entire war.

During the Cold War, NATO forces had to train constantly to fight through elaborate Soviet trench systems, a tactic that was well-ingrained in Russian military doctrine after defending against Nazi Germany in WWII. Both Korea and Vietnam also had their fair share of trench and tunnel warfare.

Decades later, trenches made another appearance during the. Even the siege on Sarajevo during the mid-90s resulted in a complex trench system due to the constant threat of sniper fire.

Today, the that separates the Korean Peninsula between north and south is built up with a dizzying array of trenches, fortified emplacements, deep tunnels, pillboxes, obstacles, and other seemingly antiquated tactics, not to mention millions of land mines. Other places, like in the Kashmir region that separates India and Pakistan, you'll find similar setups, and if a conflict occur between those two countries, it will likely play out among those fortifications and trenches.

In some ways, trench warfare and the tactics associated with fighting in such an inhospitable and unforgiving environment was the precursor to what we know today as urban warfare. Although urban combat has dominated tactics doctrine for the last decade and a half, the reality is that the US has tens of thousands of troops in South Korea, a place where the front lines would require both urban and trench warfare fighting abilities if that conflict ever went hot.

So while it's nice think that mankind has left such a seemingly horrendous and futile form of warfare in the past, the truth is anything but, and you can see it in action as the 2nd Calvary Regiment clears trenches in Poland in the video above.