WHat happen to have the price go up and down

When you trade (specifically in crypto) you know that price go up because ask increase or price go down because offer increase.
But specifically, where can we have more information about it. when there is a big rise or a big down on the price, probably something important happen on the market. Is there any place where we can know about it?

Thanks guys.

Any clue on what happen yesterday and why all Crypto has lost almost all 10% of their value?

President trump talked about crypto being made up. It was mainly over the Facebook coin that will be a complete ripoff. But I’m with a lot of people… it’ll come back 10 fold.