Funny that you mention gas pipe.
In an old 19th-century tenement that my uncle lived in at one time, there was a gas jet on the wall in one of the rooms. But my now 60-year old uncle didn't know what that thing was - he had never seen one, having grown up in a city in Colombia with electric lights, candles and the occasional kerosene lamp.
Since he wanted to put some furniture against that wall, he decided one of those days he was going to take a hacksaw and cut the pipe off and then plaster the hole over.
One day he and the building super were talking and my uncle happened to mention this funny pipe sticking out of the wall and that he was thinking of cutting it off.
The super got scared and said "Don't cut that off!! That's part of the gas!" Then he went on to explain to my uncle that the building was from before the days of electric lights, so those pipes were for lighting up the room with gas flame.
