The explanation behind 6 popular design elements on buildings

Said to have origins in Charleston, South Carolina, in the late 1800s, "haint blue" is the color used to paint the ceilings of front porches in order to repel spirits. 

The belief is that spirits are unable to cross water, so the blue color would trick them into thinking the porch ceiling was actually a body of water.

Generally, "haint blue" is quite light and it has come to be just about any blue-green color. It's also a popular porch-ceiling color throughout the US, likely because it looks a bit like the sky and helps create the illusion that daylight lasts longer. 

Popular in New England, particularly in Vermont, "witch windows" are angled windows that are often found between roofs on the upper levels of a home.

As Devin Colman, who works for Vermont's Division for Historic Preservation, told Vermont Public Radio, "The story is that a witch on a broomstick can't fly through a crooked window opening, which I guess physically is true."

These are also known as "coffin windows," according to Colman, possibly because they could accommodate a coffin coming in and out of the upper floors. "The idea being that it's difficult to maneuver a coffin with a body from the second floor down to the first floor in these narrow staircases, so slide it out through the window and down the roof." 

That said, these windows also maximize an awkward sloping space, serving the practical purpose of adding more light and a breeze to an upper story of a home. 

Next time you're in an elevator inside of a tall building in the US, there's a good chance you won't see the number 13 as it's quite common in the US for high-rise buildings and hotels to avoid having a 13th floor.

This is often tied to triskaidekaphobia, a dislike of or superstition regarding the number 13. Generally, in the US, the number is considered to be unlucky.

Sometimes, the elevator will simply go from floor 12 to 14 or the number 13 will be replaced with the letter "M." 

In addition to skipping the 13th floor, some tall buildings in East-Asian countries, such as China or Japan, will also avoid having elevators that go to any floor that involves the number four — it's not uncommon to go from the 12th floor to the 15th floor or third to the fifth. 

Once again, this number omission is tied to superstitions. In some East-Asian countries, it's somewhat common to believe that four is an unlucky number and this is tied to tetraphobia, a fear of the number four.

In some states around the US, such as Pennsylvania and Ohio, you'll often see large stars mounted on houses and barns.

Believed to have Pennsylvania-Dutch or German roots, these stars were once painted on barns to ward off evil and they were oftentimes referred to as "hex stars." They commonly used to feature six, eight, or 12 points and were located within a circle or square. 

Decades later, people began selling the stars as metal art pieces that could be easily mounted on a building. They've since evolved to have five points and are now often viewed as a sign of luck.

Many churches or cathedrals featuring Gothic architecture are adorned with small gargoyle creatures that are quite practical. These stone features typically have spouts in their mouths that help to drain water away from a building, much like a rain gutter. 

In addition to draining water, some believe these highly visible, horrifying creatures were also meant to serve as a reminder of the horrors of hell that sinners would face if they didn't seek salvation inside the church.