Barack Obama did what no sitting U.S. president has done before - recall the annihilation of the atom bomb in the very city it reduced to ashes.

Before embarking on an emotionally-charged speech, Mr. Obama later wreath in memory of approximately 80,000 men, women and children who died

when the U.S. became the first and only country to use an atomic bomb on the 6th of August, 1945.

Then Japan's Prime Minister, Shinzo Abe, laid a wreath in turn.

Mr. Abe bowed, Mr. Obama did not.

Then the two men shook hands, a symbol of the 70-year U.S.- Japan friendship that grew from the devastation of war.

71 years ago death fell from the sky and the world was changed, said Mr. Obama, addressing an audience that included hibakusha, survivors of the bombing.

We've come to ponder a terrible force unleashed in a not-so distant past.

But we have a shared responsibility to look directly into the eye of history, and ask what we must do differently to curb such suffering again.

The U.S. president made clear he was not apologizing, addressing troops at a U.S. marine core base near Hiroshima earlier in the day.

A choreography to show strength as well as sorrow,

he said the visit was an opportunity to honor the memory of all who were lost in World War II.

It's a chance to reaffirm our commitment to pursuing the peace and security of a world where nuclear weapons would no longer be necessary.

And it's a testament to how even the most painful divides can be bridged,

how our two nations, former adversaries, can not just become partners, but become the best of friends and the strongest of allies.

Mr. Obama's visit is a powerful symbol of reconciliation between the U.S. and Japan, former enemies who have become close allies.

Opinion polls show an overwhelming majority of Japanese are pleased Mr. Obama is visiting now even without an apology,

after U.S. presidents avoided the site for 71 years.

The visit also symbolizes some of the frustrated ambitions of Mr. Obama's presidency.

In the 7 years since his landmark speech in Prague, where he said the U.S. has a moral responsibility to rid the world of atomic weapons,

Russia, China and others have modernized their atomic arms.

Leo Lewis, Financial Times, Tokyo.