Brisieis

I agree.

Panthera tigris altaica

Geez, couldn't the OP have given us more choices?

Sankari

Erm... what? I counted one invasion: Iraq.

Ancientgeezer

It' too early to tell.

AlpinLuke

Yes, actually we cannot know ...

in the first 20 years of this era no one was aware that they were living in the Christian age, since the Christ was still to come [but, he was already alive].

Moreover, on last 13rd December 2011 at CERN LHC has seen some sights which could suggest the "passage" of Z bosons [the notorious Higgs bosons, the particles of God].

If in the following years this will be confirmed, 12-13-2011 will become a historical date in science.

Again, consequences in the long term of events above mentioned can change the order of importance.

So, probably we have to wait.

Vladimir

It would be rather unrealistic to posit that in the first decade of the 21st century there has been a more historically significant moment than 9/11. We've lived through the first decade since those planes crashed, and it's not far-stretched to say it had the largest impact on global politics and global economics in the 21st century. As we dawn into the second decade of the century, the Arab Spring and the economic crisis experienced by the West, are the two events that have the greatest potential to influence further historical development in the 21st century.

Mohammed the Persian

The Israelis pulling out of Lebanon and then going back in 6 years later. Ring any bells ?

The Libya military intervention . Not an invasion but still interference.

And you can count Afghanistan, if you include it in your definition of the Middle East

Ancientgeezer

I'll bet there was a bunch of gentlemen sitting in the Cavalry Club in say, January 1912, discussing whether the Boer War or the Russo-Japanese war were the big events of the century and congratulating themselves that Britain had no entanglements with the continent where trouble was brewing in the Balkans and was safe behind its wall of super-dreadnaughts.

Winkpolve

EURO. To be honest, 9/11 was just a media adventure set up by the American government, so I’m not surprised. The adoption of the EURO as a "continental currency" was a reinforcement of the European Union, making it practically borderless (except for cultural and historical differences). It changed the meaning of Trade Blocs and merged international relations between European countries, given the huge economic diffences between them.

mofli87

In my opinion the arabic spring..
911 had only simpbolic global effect (and improved the security).
On the other hand the arabic uprisings changed the status quo in Northern Africa, and we still don't know the results of these event.