I think in terms of peace it's useful to distinguish between the EU and Europe. There have been a couple of wars in Europe in my lifetime. Not to mention a few military dictatorships (which had a kind of 'peace' I suppose - but not a good one), assassinations of leaders etc.
Maybe (hopefully!) we'll get through this without it imploding - maybe end up with a more Hanseatic League kind of set up, maybe more like the US. 'May you live in interesting times' and all that... ;-)
I would also question whether this period of peace in Europe is really due to the EU. The EU and it's predecessors certainly contributed to it, but I would argue it's a marginal contribution. If you look at world history after WWII you see that major conflicts - between two powerful nations - have largely disappeared. Instead we got a slew of proxy wars: US vs. China in Korea, US vs. China/USSR in Vietnam or Iran vs. Saudi Arabia in Syria more recently. I think the reason for this is purely economical. No country can afford in the late 20th century to break all diplomatic ties with another country (and their allies), so instead of engaging in an all out war they support local regimes or mercenaries whilst maintaining the necessary economic relations with supporters of opposing regimes. In Europe meanwhile the economies have become so interconnected (even before the EU) that any war would mean economic devastation for the whole region and is thus an impossible course for any regime.
I think the EU certainly helped a lot by trade and free movement of people. It's a lot harder to make people from another country into demons if you've met them and shared a bottle of wine with some of their (almost inevitably from a UK perspective, better) food. Not impossible - but much harder.
I think we've had proxy wars by major powers going back millenia - I don't think that's such a strange situation for Europe compared to free movement and cheap flights.
It's unthinkable at this point for any of the large nuclear powers (e.g. the permanent members of the UN security council) to engage each other in direct military confrontation. Barring an early armistice, there's a high likelihood of human extinction as soon as one side gains the upper hand and the other side believes it has nothing to lose.
Much safer for everyone to expand their sphere of influence through proxy wars.
"I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones."
I think in terms of peace it's useful to distinguish between the EU and Europe. There have been a couple of wars in Europe in my lifetime. Not to mention a few military dictatorships (which had a kind of 'peace' I suppose - but not a good one), assassinations of leaders etc.
Maybe (hopefully!) we'll get through this without it imploding - maybe end up with a more Hanseatic League kind of set up, maybe more like the US. 'May you live in interesting times' and all that... ;-)