I think the main reason is the US beat Syria. This is the main reason that has pushed up so many altcoin prices. People are pouring money into the Crypto market to hold their assets in BTC. So altcoin prices have rebounded in two days.
It seems people will always speculate and find a reason for a particular action in the market. It is a speculative market anyway, so we should always expect some few little things to affect the market value once in a while. Nevertheless, we cannot say exactly what must have triggered that value, as it may not even be any of that, but whichever way, the price shot up but the question now is can we continue with this trend or we are going to still go back lower ? Let's see how it plays out in time.
Reasons foe the rise in Bitcoin value can be the only reason and that is the demand of people all over the world people are in positive mood about Bitcoin due to its functions and advantages and solution for their problems that is why the whole world is crazy for it to put up with in the right means. Other than this the positive news also plays a good role that encourages people to invest.