Where did spaghetti carbonara originate?

The Vicolo della Scrofa, for those who know Rome, is one of the most characteristic streets and rich in symbols. Precisely in a trattoria on this street, from which the name of the alley, it seems that the first carbonara was made, in 1944.

The most reliable story about this first course, in fact, tells the meeting between the ingredients available to American soldiers and the imagination of a Roman cook.
The result was the prototype of spaghetti carbonara: eggs, bacon (then guanciale) and cheese. The recipe has gradually evolved to the one we all know today and we can appreciate at the home of true (and voracious) Roman friends, in trattorias as well as in starred restaurants in the capital, throughout Italy and abroad, in the countless versions: with or without pepper, with one yolk per person or the addition of at least one whole egg, with guanciale or streaky bacon. 
The main rule? 

There is no cream in a real Carbonara!