I’m doin a Project and i need to know where and when the BC wheel came to this planet earth and who invented it would be nice also. 
look at the name… BC Wheel. haven’t you ever seen the comic strip BC?
If I had to guess, I’d say someone probably first did it during the 1890s. It could have been a hobbyist or a professional performer. If it was a hobbyist and it never got written up, we’ll probably never know. If it was an entertainer, there may be records of it in show fliers and things. I’ve seen posters and other ad materials from turn-of-the-century performers, and they show things like ultimate wheels, square wheels, half-wheels, big wheels, handlebar unis, etc.
In the world of English-language, “organized” unicycling (like the Unicycling Society of America, newsletters and conventions & stuff), the earliest reference that comes to my mind is Sem Abrahams, who had a BC (or “impossible”) wheel possibly at the 1979 National Unicycle Meet in Findlay, Ohio. Don’t know if he had it there, but he did have it in 1980 in Kokomo, Indiana. Tom Miller also had one around the same time, but I think Sem’s may have come first. Next thing would be to ask him where he got the idea, or if he saw others do it first.
The name of course comes from the comic strip by Jonny Hart.
It seems to me that if flatland BMX was something like it is today 30 years ago, than a BMX rider would be the most likely one to have invented the modern BC wheel. From the videos I have watched, it seem that most flatland BMX consists of coasting around while standing on pegs on the front wheel, and holding the rear wheel and frame in the air. It seems to me, that for someone who was already adept at these flatland biking skills, removing the rear wheel and frame would have been a rather obvious step. It shouldn’t even have required building any special equipment, provided the rider already had a good freestyle bike. Such a person would also already have had most of the reflexes for riding a BC wheel.
Many flatland riders ride ‘un-bikes’. These consist of the front wheel, fork, and bars. Next logical step is to take the wheel off and just ride that; whether someone did it before flatland riders or not, it independently arose there.