The origin of the modern spiral staircase

Today, spiral staircases are an extremely common feature, as their winding treads and weaving balustrades provide not only an elegant aesthetic, but they also work wonders in saving space. This is especially true in cramped areas or elevations that are difficult to access.

The first spiral staircases came about not for aesthetics but solely for their functionality. In medieval times, spiral staircases were actually part of the military strategy used to help warring kingdoms in feudal England.

One of the signature architectural structures of the time was the elaborate fortress-like castle, complete with a moat, drawbridge and, perhaps most noticeably, large towers and turrets. Although these towers and turrets were great ways to show a kingdom's power, they were also extremely effective ways to watch out for intruders as well as attack from on high.

Spiral staircases allowed soldiers to travel up the length of the tower through the core, letting defenders shoot their bows and arrows out of the thin windows that ran up the side of the turret.

These staircases were almost always built with the spiral in the same direction - clockwise when viewed from the bottom - so that the defending swordsman, who would either be coming down the stairs or backing up in reverse, could freely swing his sword. On the flip side, the attacking swordsman, who would be ascending the stairs, would have his swing blocked by the wall.

Spiral staircases weren't just used in the castles of feudal England but in structures throughout the medieval world. Palaces in the Middle East built during the crusades to defend the Holy Land have staircases like this. 

Perhaps the oldest spiral staircase that is still in use today can be found within Trajan's Column in Rome, which was constructed in 155 A.D.