Conflict photographers grapple with two worlds that are themselves often in conflict - the one where bombs fall and bullets fly, where adrenaline runs high, and the other, back home, which is comparatively secure, and where the big event of the day may involve selecting swatches of fabric for a new sofa.

Life feels more vivid in a conflict zone. It is clear what matters, and who you can count on, for what.

Long-distance train conversations are unlike the perfunctory exchanges one normally associates with strangers, or the truncated, cut-to-the-chase kind that sometimes take place between seatmates on a plane.

Right up until the late 18th century, when the first weighted lines were used to probe the ocean depths, many people believed the seas were bottomless - the watery equivalent of infinite outer space.

I will not shy away from the prospect of peace because I believe our people, and any people, should have something to believe in.

There cannot be enduring peace, prosperity, equality and brotherhood in this world if our aims are so separate and divergent, if we do not accept that in the end we are people, all alike, sharing the Earth among ourselves and also with other sentient beings, all of whom have an equal role and stake in the state of this planet and its players.

When I went down to London in '67, I had three things in mind: To survive, to find peace of mind, and to make music doing it.

The choice, however, is as clear now for nations as it was once for the individual: peace or extinction.