Before elevators and escalators, how did people get up and down? Stairs, of course! Let's take a closer look at this invention…one step at a time.

A flight of stairs — also called a stairway, staircase, stairwell or just stairs — does the simple job of dividing a large vertical gap into smaller vertical gaps called steps. Without stairways, we'd have a hard time climbing to the tops of buildings…or buildings would be a lot shorter!

Stairways can take many different forms. They can be straight or round. They can also consist of multiple straight pieces positioned at angles and connected by small landings.

Stairways are made up of individual steps. Each step consists of a tread and a riser. The tread is the flat part that you step on. The riser is the vertical (up and down) part between each tread in the stairway.

So how many steps are in a “flight" of stairs? A flight of stairs is usually defined as an uninterrupted series of stairs. This can mean the set of stairs between floors or the set of stairs between landings. The term is used in many different ways and there's really no set rule for what can be called a flight of stairs.

The number of stairs in a flight can vary widely. It depends upon the building they're located in and how much space there is between floors in the building. The next time you climb a flight of stairs, count the stairs. For example, how many stairs are in the flights of stairs in your school? You may be surprised to learn that the number of stairs in a flight can even vary within the same building!

If you're wondering why it's called a “flight" of stairs, it's probably because “flight" is a metaphor for a journey upward — only using the feet instead of wings! The next time you run up a flight of stairs, think of yourself as “flying" up them.

And speaking of taking the stairs, do you climb stairs when an elevator or an escalator is available? If you don't, you might want to reconsider the next time you have the chance. Climbing stairs can give your body much needed exercise during the day.

If you really want to burn some calories, you might want to consider climbing the longest stairway in the world. The service stairway for the Niesenbahn railway near Spiez, Switzerland, holds the Guinness World Record for longest stairway. Its 11,674 steps stretch up for over a mile!

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