A museum commemorating those who lost their lives in the 9/11 terrorist attacks in New York has been heralded as "a sacred place of healing and of hope" by US President Barack Obama.
At the official dedication of the memorial on Thursday evening, Obama gave an address praising 24-year-old Welles Crowther, an equities trader who died while leading others to safety in the South Tower. One of those he rescued, Ling Young, was in the audience.
The president added that it was an "honour...to recall and to reflect, but above all to reaffirm the true spirit of 9/11 – love, compassion, sacrifice – and to enshrine it forever in the heart of our nation.
"I think all who come here will find it to be a profound and moving experience," he said.
"I want to express our deep gratitude to everybody who was involved in this great undertaking – for bringing us to this day, for giving us this sacred place of healing and of hope."
Exhibits on display at the museum – which has been described by Paula Berry, whose husband David was one of the 3,000 victims of the tragedy, as "powerful and necessary" – include the remains of a damaged fire engine, personal belongings found in the wreckage and a montage of photos to commemorate the dead.
The museum itself is underground; directly below ground zero.
"Here, at this memorial, this museum, we come together. We stand in the footprints of two mighty towers, graced by the rush of eternal waters," the president said last night.
"We look into the faces of nearly 3,000 innocent souls – men and women and children of every race, every creed, and every corner of the world. We can touch their names and hear their voices and glimpse the small items that speak to the beauty of their lives.
"Here we tell their story, so that generations yet unborn will never forget...A nation that stands tall and united and unafraid – because no act of terror can match the strength of the character of our nation.
"Like the great wall and bedrock that embrace us today, nothing can ever break us; nothing can change who we are as Americans."
The museum, which cost $700 million to build, will open to the public on 21 May.