The ladder is as old as time itself, where people looked at a tall object and figured out that they needed a way to get up there. There are two types of ladder in the world, a rigid ladder that can stand alone and is typically leaned against a wall, and a rollable ladder that is generally thrown or hung from an object. You probably have or at least have seen both types of ladder in action before, as they are quite common in today’s world.
Ladders were first used by humans 10,000 years ago, thanks to a cave painting in Spain, and have stuck around ever since. In ancient times they were used to reach high places and also used during siege warfare. This tactic was called escalade, and involved warriors charging up to the wall, raising the ladders and then climbing up the ladder to attack soldiers on the wall.
Due to the sheer amount of defenses cities and castles had to defend against this method of attack, it was primarily done as a method of infiltration. Still, with enough speed and ladders, it was a valid tactic if commanders had the men to spare, and once you had a foothold on the wall you could do some serious damage. It typically had to be done in conjunction with another type of attack to divide the defenders, and when gunpowder began to rise, the tactic fell out of favor.
In the modern day, police and special forces, teams often use ladders to raid buildings or get to a higher position quickly. But the ladder can most often be found off the battlefield in garages and other areas, such as in pools that need a 5 step dock ladder to get people in and out of the water.