These are some famous and powerful quotes that changed world history. Some of them were so powerful that World Wars took birth as they were uttered. Others quelled storms that threatened to wipe out humanity. Still, others inspired a change of mindset, and kickstart social reform. These words have transformed the lives of millions, and have etched new paths for the future generation.

Galileo Galilei

Eppur si muove! (And yet it moves.)

Every once in a century, there comes along a human being who brings about a revolution with just three words.

Italian physicist and mathematician Galileo Galilei held a different view of the movement of the sun and the celestial bodies with respect to the earth. But the church held the belief that the Sun and other planetary bodies revolve around the Earth; a belief that made God-fearing Christians adhere to the words of the Bible as interpreted by the clergymen.

In the era of Inquisition, and a suspicious wariness of Pagan beliefs, Galileo's views were considered heresy and he was tried for spreading heretic views. The punishment for heresy was torture and death. Galileo risked his life to educate the church on how wrong they were, but the chauvinist views of the church were to remain, and Galileo's head was to go. A 68-year-old Galileo could hardly afford to lose his head before the Inquisition for a mere fact. He, therefore, made a public confession that he was wrong:

I held and believed that the sun is the centre of the universe and is immovable, and that the earth is not the centre and is movable; willing, therefore, to remove from the minds of your Eminences, and of every Catholic Christian, this vehement suspicion rightfully entertained toward me, with a sincere heart and unfeigned faith, I abjure, curse, and detest the said errors and heresies, and generally every other error and sect contrary to Holy Church; and I swear that I will never more in future say or assert anything verbally, or in writing, which may give rise to a similar suspicion of me; but if I shall know any heretic, or anyone suspected of heresy, that I will denounce him to this Holy Office, or to the Inquisitor or Ordinary of the place where I may be; I swear, moreover, and promise, that I will fulfil and observe fully, all the penances which have been or shall be laid on me by this Holy Office.

(Galileo Galilei, Abjuration, 22 Jun 1633)

The above quote, "Eppur si muove!" was found in a Spanish painting. Whether Galileo actually said these words are unknown, but it is believed that Galileo muttered these words under his breath after he was forced to recant his views.

The forced recantation that Galileo had to endure is one of the most significant events in the history of the world. It shows how free spirit and scientific thinking was always stifled by conservative views of a powerful few. Humankind will remain indebted to this fearless scientist, Galileo, who we regale the "father of modern astronomy," the "father of modern physics", and "the father of modern science."

Karl Marx and Friedrich Engels

The proletarians have nothing to lose but their chains. They have a world to win. Working men of all countries, unite!

These words are a reminder of the rise of communism under the leadership of two German intellectuals, Karl Marx and Friedrich Engels. The working class had suffered years of exploitation, oppression, and discrimination in a capitalist Europe. Under the powerful rich class that comprised of businessmen, traders, bankers, and industrialists, the workers and laborers suffered inhuman living conditions. The simmering discord was already growing in the underbelly of the poor. While capitalist countries vied for more political power and economic freedom, Karl Marx and Friedrich Engels believed that it was the time the workers were given their due.

The slogan, "Workers of the world, unite!" was a clarion call in the Communist Manifesto created by Marx and Engels as a closing line of the manifesto. The Communist Manifesto threatened to shake the foundation of capitalism in Europe and bring about a new social order. This quote, which was a meek voice calling for change became a deafening roar. Revolutions of 1848 were a direct result of the slogan. The widespread revolution changed the face of France, Germany, Italy, and Austria. The Communist Manifesto is one of the most widely read secular documents in the world. The proletariat governments were elbowed out of their cushy positions of power and the new social class found its voice in the realm of politics. This quote is the voice of a new social order, that brought in a change of time.

Nelson Mandela

I have cherished the ideal of a democratic and free society in which all persons live together in harmony and with equal opportunities. It is an ideal, which I hope to live for and to achieve. But if needs be, it is an ideal for which I am prepared to die.

Nelson Mandela was the David who took on the Goliath of the colonial rule. The African National Congress, under the leadership of Mandela, held various demonstrations, civil disobedience campaigns, and other forms of non-violent protests against apartheid. Nelson Mandela became the face of the anti-apartheid movement. He rallied the black community of South Africa to unite against the oppressive regime of a white government. And he had to pay a heavy price for his democratic views.

In April 1964, at the crowded courtroom of Johannesburg, Nelson Mandela faced trial for charges of terrorism, and sedition. On that historic day, Nelson Mandela made a speech to the audience gathered in the courtroom. This quote, which was the closing line of the speech, evoked a strong response from every corner of the world.

Mandela’s zealous speech had left the world tongue-tied. For once, Mandela had shaken the foundations of the apartheid government. Mandela’s words continue to inspire millions of oppressed people of South Africa to find a new lease of life. Mandela’s quote reverberates in political and social circles as a symbol of a new awakening.

Mr. Gorbachev, tear down this wall.

Though this quote refers to the Berlin Wall that divided East Germany and West Germany, this quote makes a symbolic reference to the end of the Cold War.

When Reagan said this highly famous line in his speech at the Brandenburg Gate near the Berlin Wall on June 12, 1987, he made an earnest appeal to Soviet Union leader Mikhail Gorbachev in a bid to thaw the frost between the two nations: East Germany and West Germany. Gorbachev, leader of the Eastern block, on the other hand, was chalking out a path of reform for the Soviet Union through liberal measures such as perestroika. But East Germany, which was governed by the Soviet Union, was stifled with poor economic growth and restrictive freedom.

Reagan, the 40th US President at that time was visiting West Berlin. His bold challenge did not see an immediate impact on the Berlin Wall. However, the tectonic plates of the political landscape were already shifting in Eastern Europe. 1989 was the year of historic significance. That year, many things came crumbling down, including the Berlin Wall. The Soviet Union, which was a powerful confederation of states, imploded to give birth to several newly independent nations. The Cold War that had threatened a worldwide nuclear arms race was finally over.

Mr. Reagan's speech may not have been the immediate cause of the breakdown of the Berlin Wall. But many political analysts believe that his words stirred an awakening amongst East Berliners that eventually led to the fall of the Berlin Wall. Today, many nations have a political conflict with their neighboring countries, but rarely do we come across an event in history that is as significant as the fall of the Berlin Wall.