Ten years ago - December 25, 1991 - marked one of the pivotal moments of the 20th century. It was the day the Soviet Union formally ceased to exist, ending more than 70 years of communist rule and decades of Cold War tensions.

The disintegration led to the creation of several newly-independent nations and new alliances. Yet at the core remains Russia: the once mighty center of the Soviet superpower, now in the throes of change and in search of a new post-Cold War identity.

Marking 10 Years After Soviet Union's Demise

On a cold winter day, the bells of the Kremlin clock tower ring out over Red Square. The tower has long adorned this historic square, but only in recent years have church hymns again become commonplace.

Marking 10 Years After Soviet Union's Demise

Public religious worship was not allowed under the atheistic communist state. Now, the little church on the far corner of Red Square is packed with worshippers.

Marking 10 Years After Soviet Union's Demise

The square also gets plenty of visitors. Fifty-three year old Yevgeny Solomkin comes to Red Square often and remembers being here during Communist holidays.

He says even from childhood he remembers the big parades on May 1 to mark victories of the Communist Revolution.

For decades Red Square was where Soviet leaders watched as row upon row of troops, tanks, missiles and other military hardware paraded by in a show of force designed to impress and intimidate.

Moscow was the core of Soviet might, whose control spread from the Berlin Wall to the Pacific Ocean, from the Arctic Circle to the steppes of Central Asia. The superpower rivalry with the United States and Cold War animosity resulted in tensions and proxy wars that spanned the globe from Cuba to Angola, from Vietnam to Afghanistan.

All that has changed. The Soviet superpower is no more. Oddly enough, the beginning of the end was ushered in by a young party functionary, who was determined to open up and reform the system in the 1980s. His name was Mikhail Gorbachev and his policies of "perestroika" and "glasnost" became household words around the world.

In a speech in 1989, he signaled an important departure from the Soviet past.

"We have refused the monopoly of truth. We don't think we are necessarily the best and that we are always right in everything and that whoever doesn't agree with us is our enemy. From now on we will be led by the principle of freedom of choice by the principle of dialogue and acceptance," Mr. Gorbachev said.

Mr. Gorbachev never intended to abandon Communism, just reform it. But what followed was the unraveling of the Communist system and the USSR. On August 18, 1991, Communist hard-liners launched a coup - a last ditch effort to hold on to power.

Mr. Gobarchev, vacationing in the Crimea, was placed under house arrest and troops were called out into the streets. Thousands of Russians also came out to demonstrate against the coup. Irina Donskaya was among those outside the White House, the seat of the Russian parliament in Moscow. She says she was angry at the hard-liners, those who had detained Mr. Gorbachev and now wanted to turn back the clock.

"I was angry because Gorbachev gave us a gulp of freedom at that time and [the hard-liners) wanted us to live according to their rules, telling us what we are to think about, how we are to think and even what we should eat and drink. I stood for freedom, if I can say so for freedom to just live my own life, not the life these communist leaders wanted me to live, but my own life," she said.

There to encourage the opponents of the coup and to convince the military not to move against them was Boris Yeltsin, head of the Russian Republic within the USSR. Standing atop a tank outside the White House, Mr. Yeltsin denounced the coup plotters.

"Citizens of Russia, on the night of 18-19 of August, the legally elected president of the country was removed from power. Regardless of the reasons given for his removal, we are dealing with a rightist, reactionary, anti-constitutional coup accordingly, we proclaim all decision and instructions of this committee to be unlawful," Mr. Yeltsin said.

In the end the coup failed, and one by one the former Soviet republics proclaimed their independence. On December 25, 1991, Mikhail Gorbachev announced his resignation and the dissolution of the Soviet Union.

"Dear Compatriots, due to the current situation and considering the establishment of the Commonwealth of Independent States, I quit my activities as President of the USSR. I am taking this decision based on my principles. I leave my post in concern, but also with hope, with belief in you, your wisdom and strength of spirit," Mr. Gorbachev said.