It was all the Romans who built it and there ideas not one in general
Pericles had the idea to build the Parthenon.
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Milana Quin
Edouard Laboulaye
Theodore Roosevelt is generally attributed with the idea because he started the canal, but I am fairly sure that sailors had that idea as well but they were not in the place to do something about it and so they just dreamt about it.
Julian Radice built it for all the beautiful women in Jordan (god helped him have sexy time)
taps, baths, showers, hoses you get the basic idea
The idea to build the Great Wall of China belonged to Emperor Qin Shihuang. The wall was built by ordinary people who lived in China at that time.
The Louvre palace, built in 1190 by King Phillip III, as a fortress, was later enlarged and modified by Charles V.
it was winston churchills idea
Odysseus got the idea.
Prince Albert thought up the idea to have the Great Exhibition, it's purpose was to gather as many artefacts and inventions from all over the world to increase international trade. I hope this helps :)