Wednesday marks 78 years since an atomic bomb was detonated over Nagasaki in World War Two, killing tens of thousands of people. The city will reflect on the death and destruction caused by the attack, and call on world leaders to do more to rid the world of nuclear weapons.

People have been gathering to pray at Nagasaki Peace Park since the early morning hours. It is located near the explosion's hypocenter.

A 18-year-old man at the Memorial Park said, "I think our generation will be the last to be able to directly listen to the voices of people who experienced the war and convey them to future generations. I have listened to survivors of the war and am trying to fulfill my responsibility."

A Catholic mass was held at a cathedral near the park. Speaking outside the cathedral, an 82-year-old woman said, "Nine relatives of my husband's side died because of the atomic bombing. So, today I came here to pray that they can rest in peace eternally. Especially on this anniversary of the atomic bombing of Nagasaki, I earnestly wish for world peace."

This year's memorial has been scaled down due to the severe tropical storm approaching the region. Neither Prime Minister Kishida Fumio nor any foreign ambassadors will be attending.

The memorial has also been moved from the city's Peace Park to a convention center. Nagasaki says it is the first time in 60 years that the event will be held indoors.

Nagasaki Mayor Suzuki Shiro will deliver a "peace declaration." He is expected to call on world leaders to stop relying on nuclear deterrence and move steadily along the path toward abolishing nuclear weapons.

Both of Suzuki's parents are among the survivors of the atomic bombing, who are known as "hibakusha."

This year's ceremony comes after world leaders gathered in Hiroshima for the G7 Summit in May.

One document that emerged out of the talks was the "Hiroshima Vision." It is a commitment from G7 leaders to seek a world without nuclear weapons.

But some hibakusha have criticized it for reaffirming the need for nuclear deterrence.

The anniversary also comes almost 18 months after Russia invaded Ukraine. Since then, Moscow has repeatedly threatened to use nuclear weapons.

Many in Nagasaki are hoping world leaders are heeding their voices so their city will forever remain the last place on Earth to suffer a nuclear attack.