The decision to use the atom bomb on Japanese cities, and the consequent buildup of enormous nuclear arsenals, was made by governments, on the basis of political and military perceptions.

I appeal to my fellow scientists to remember their responsibility to humanity.

There is no direct evidence that nuclear weapons prevented a world war. Conversely, it is known that they nearly caused one.

I did not imagine that the second half of my life would be spent on efforts to avert a mortal danger to humanity created by science.

Indeed, the very first resolution of the General Assembly of the United Nations - adopted unanimously - called for the elimination of nuclear weapons.

From my earliest days I had a passion for science.

To sum up, there is no evidence that a world without nuclear weapons would be a dangerous world. On the contrary, it would be a safer world, as I will show later.

The most terrifying moment in my life was October 1962, during the Cuban Missile Crisis. I did not know all the facts - we have learned only recently how close we were to war - but I knew enough to make me tremble.

The Cold War is over but Cold War thinking survives.

If the militarily most powerful - and least threatened - states need nuclear weapons for their security, how can one deny such security to countries that are truly insecure? The present nuclear policy is a recipe for proliferation. It is a policy for disaster.

The present basic philosophy is nuclear deterrence.

At a time when science plays such a powerful role in the life of society, when the destiny of the whole of mankind may hinge on the results of scientific research, it is incumbent on all scientists to be fully conscious of that role, and conduct themselves accordingly.

The time has come to formulate guidelines for the ethical conduct of scientist, perhaps in the form of a voluntary Hippocratic Oath.

We are told that the possession of nuclear weapons - in some cases even the testing of these weapons - is essential for national security. But this argument can be made by other countries as well.

I saw science as being in harmony with humanity.

So I ask the nuclear powers to abandon the out-of-date thinking of the Cold War period and take a fresh look. Above all, I appeal to them to bear in mind the long-term threat that nuclear weapons pose to humankind and to begin action towards their elimination.

But the nuclear powers still cling tenaciously to their weapons.

Let me remind you that nuclear disarmament is not just an ardent desire of the people, as expressed in many resolutions of the United Nations. It is a legal commitment by the five official nuclear states, entered into when they signed the Non-Proliferation Treaty.

I have to bring to your notice a terrifying reality: with the development of nuclear weapons Man has acquired, for the first time in history, the technical means to destroy the whole of civilization in a single act.

When the START 2 treaty has been implemented - and remember it has not yet been ratified - we will be left with some 15,000 nuclear warheads, active and in reserve. Fifteen thousand weapons with an average yield of 20 Hiroshima bombs.

This is the reality of nuclear weapons: they may trigger a world war; a war which, unlike previous ones, destroys all of civilization.

But scientists on both sides of the iron curtain played a very significant role in maintaining the momentum of the nuclear arms race throughout the four decades of the Cold War.

Since the end of the Cold War two main nuclear powers have begun to make big reductions in their nuclear arsenals. Each of them is dismantling about 2,000 nuclear warheads a year.

The chief task was to stop the arms race before it brought utter disaster. However, after the collapse of communism and the disintegration of the Soviet Union, any rationale for having nuclear weapons disappeared.

The decision to use the atom bomb on Japanese cities, and the consequent buildup of enormous nuclear arsenals, was made by governments, on the basis of political and military perceptions.

My third appeal is to my fellow citizens in all countries: Help us to establish lasting peace in the world.

Indeed, the whole human species is endangered, by nuclear weapons or by other means of wholesale destruction which further advances in science are likely to produce.

As for the assertion that nuclear weapons prevent wars, how many more wars are needed to refute this arguments? Tens of millions have died in the many wars that have taken place since 1945.

All nuclear weapon states should now recognize that this is so, and declare - in Treaty form - that they will never be the first to use nuclear weapons. This would open the way to the gradual, mutual reduction of nuclear arsenals, down to zero.

Several studies, and a number of public statements by senior military and political personalities, testify that - except for disputes between the present nuclear states - all military conflicts, as well as threats to peace, can be dealt with using conventional weapons.

Long before the terrifying potential of the arms race was recognized, there was a widespread instinctive abhorrence of nuclear weapons, and a strong desire to get rid of them.

But the first the general public learned about the discovery was the news of the destruction of Hiroshima by the atom bomb. A splendid achievement of science and technology had turned malign. Science became identified with death and destruction.

This means that the only function of nuclear weapons, while they exist, is to deter a nuclear attack.

There are certain romances that belong in certain cities, in a certain atmosphere, in a certain time.

And I think I find, I know a lot of people around, in different cities, and so it's not - it might sound strange - but it's not that hard to say good-bye, because I know there's other people where I'm going. I can sort of fit in in a lot of places.

In addition to a timeline, I have proposed that U.S. troops be removed from front line combat positions in Iraqi cities and towns, turning over daily security patrols, interactions with citizens, and any offensive security actions to the Iraqis themselves.

We ought to be doing that with decent standard housing but if we have people who are absolutely on the streets in this case, I think it makes sense that tent cities are preferred to not having tent cities.

Our fifty principal cities contain 39.3 per cent of our entire German population, and 45.8 per cent of the Irish. Our ten larger cities only nine per cent of the entire population, but 23 per cent of the foreign.

Divine Nature gave the fields, human art built the cities.

Unlike most major American cities, Honolulu is geographically insulated from the rest of the country. When disaster strikes we cannot call on neighboring states for assistance.

I'm always going to get more of a charge playing Chicago than I will Duluth or some place like that. Just because of the history and the people there are way more knowledgeable than a lot of other cities. It's an amazing music scene with some great bands and great musicians.

We do not look in our great cities for our best morality.

Have you ever, on a cloudless night, looked down from a passing aircraft flying over Canada? Endless, glowing strings of cities, towns, and homesteads. Stretching on and on, one province to the next. With only the stars in the distance.

Australia as a nation, as a set of cities and some regional centres, that project died a death and we didn't get it up, but I still think there's merit in that.

Burn down your cities and leave our farms, and your cities will spring up again as if by magic; but destroy our farms and the grass will grow in the streets of every city in the country.

The point of cities is multiplicity of choice.

I can set up shop anywhere. I've got my oils, I've got my yoga mat and I'm good to go. I must know good yoga classes in about 25 cities on this planet.

What I'm going to be given I gather is not the key to the city, which in many cities is the case. It's the freedom medal, and for me freedom has always been associated traditionally within the city.

It is we the workers who built these palaces and cities here in Spain and in America and everywhere. We, the workers, can build others to take their place. And better ones! We are not in the least afraid of ruins.