The euro's tumble below $1 for the first time in two decades puts it on course for one of the worst years in its history, especially if the energy price shock triggered by the Ukraine conflict tips the bloc into a prolonged economic crisis.

The single currency has teetered on the brink of parity versus the greenback for days, finally breaching that level on Wednesday. Its 11.8% year-to-date fall is almost on par with losses seen in 2015, the year the European Central Bank unleashed massive stimulus.

Wednesday's move may open the doors for a move towards $0.96, analysts predict, with some expecting a fall to $0.90 if gas supplies are disrupted much further.