Russians have held various official and unofficial celebrations to mark the anniversary of Crimea's rejoining Russia. A documentary called Crimea: Way Back Home has gone viral. Russian President Vladimir Putin's impassioned speech at a concert at the Red Square on Wednesday has given another push to Russia's patriotism.

Controversial it is, Crimea's reunification with Russia has already become a landmark event of the post-Cold War era. However, the change of Crimea's ownership, which was hailed as the "return home" of Crimea to Moscow's control by the Russians, is probably just a humiliation to the Ukrainians. Meanwhile, the West's accusations of a Russian "invasion" are not accepted by the Russians, who claim that Crimea's return is a historically legitimate and natural case.

The lack of agreement over the nature of the Crimea issue does not prevent all parties involved agreeing to the fact that the crisis has become a political symbol, which heralds the eventual failure of an ongoing security architecture summoned by the international community after the Cold War.

The abrupt end of the Cold War has failed to guarantee that a new security architecture well established and preserved. Psychologically, the Westerners view themselves as victors in the Cold War, while the Russians are not reconciled to the fact that they lost the Cold War.

The dilemmas of realism and the psychological gap between Russia and the West have turned out to be the biggest challenges before they can establish a security agreement. In the limbo where the old pattern has been disrupted but a new one is yet to be established, any provocative unilateral move will complicate the already unpredictable situation.

From a Russian perspective, NATO and the EU's eastern expansion has encroached on Russia's strategic territory, preventing the former superpower from rising again. As for the West, in a bid to avoid a new "empire" emerging on the Eurasian continent, they have to make sure the outcome of the Cold War cannot be reversed.

From a Western viewpoint, Russia has ambitions to return to imperial status, because the Putin-led Kremlin holds the entire former Soviet Union's domain as its sphere of influence, and it is gaining more power from its energy exports.

What's more, the EU and Russia has not managed to find a common ground on how to re-demarcate the domains of the former Soviet Union, so a tit-for-tat game always prevails. From Putin's aggressive speech at the Munich Conference on Security Policy in 2007 to the war with Georgia in 2008, and then to Crimea's integration with Russia, Moscow is determined to continue its counteroffensive whatever happens.

It appears that Crimea's fate cannot be reversed. There is not much realistic significance in talking about its history and ownership any more.

It signifies the fact that the legacy of the Cold War has not been dealt with in a proper manner, and unstable elements might be re-ignited to cause more turbulence.

The NATO and EU's ruthless exclusion of Russia from the entire European security architecture has prompted Moscow's antagonism and unilateralism against the West. Such strong reactions have drawn comment by practical international relations experts such as Henry Kissinger and John Mearsheimer.

This year marks the 70th anniversary of the end of WWII. That part of history still bears practical significance. Before the WWII began, there was a 20-year-long crisis in Europe, where contradictions could not be resolved in peace but by war. Do we have to go through another 20-year crisis in this post-Cold War era? Let's hope not.

The author is an associate research fellow with the Institute of Russian, Eastern European & Central Asian Studies at the Chinese Academy of Social Sciences.