You are possibly aware of the current political situation in Italy, that has again put into question the sustainability of Italian debt.
This is the beginning of the end for the euro. The next three months are going to be a barrage of bad news for the EU economy. By October, economists will be openly talking about ending the euro. By the end of the year, the discussion will have moved from "should we give up on the euro?" to debating the specific steps to follow in order to undo the monetary union.
Fall of the euro could trigger the next global economic downturn. If Trump foolishly initiates a trade war, this will compound global economic instability and is likely to make a bad situation worse.
If the Euro is eliminated, what will take its place? Will EU countries go back to their original currencies?
What you might see is some countries "decoupling" from the Euro and going back to their own currencies in order to let their currencies "float" (or lose value) as a way of relieving debt pressure.