What would the World be like without Rome?

Question

In about 390 BC, Celtic soldiers (possibly mercenaries) sacked Rome - Rome broke one of the Celts rules of conduct and refused to make amends. After 3 months of siege, the Celts agreed to pull out (whether due to weakening strength of the Celtic army, or due to disgust at a "city" depends on which you believe). One report I have seen says that the agreement was "we will leave you alone if you leave us alone". Either way, the Celts left Rome alone, long enough for Rome to establish its powerful Empire within a few hundred years, while improving military tactics, shamed by their defeat.

What would the world be like had the Celts utterly destroyed Rome instead? Would the Celts eventually have been conquered by another culture, or would they have been strong enough to defeat the Angles, Normans, Saxons, and Vikings? Would Israel have given rise to Christ, without Rome? Would the Europeans have wanted to conquer America? What would our language be like?

Answer 1

One of the possible outcomes would be the domination of Carthage in the Mediteranean. Which means that today we just might be throwing babies into the fire as part of religious ceremonies
There would have been more languages, and many, much smaller, nations. Probably many more wars.
Definetly yes on the conquest of America- that was a ripe plum waiting to be picked and no commercially minded culture would have passed up such an opportunity.
Definetly yes on the ownership of slaves- the single most effective reason for it's elimination was Christianity

No difference that I can see to the Hun invasions, and later on to the Mongol invasions.Quite possibly, without the existence of Rome, the end result of these migrations would have been the complete extermination of any symptoms of civilisation in Europe

Answer 2

someone else would have stepped in, in romes place