A city rebuilt from the ashes : Hiroshima-Nagasaki Then and Now.

Exactly 73 years ago the US dropped an atomic bomb, nicknamed Little Boy, on Hiroshima, killing 140,000 of its 350,000 citizens. Three days later, a second bomb, Fat Man, was dropped on Nagasaki. Photographer Issei Kato has paired archive images of the ruins with how they look today:

• The gutted Hiroshima Prefectural Industrial Promotion all – now known as the A-Bomb Dome or the Hiroshima Peace Memorial – after the bombing on 6 August 1945, and the same location near Aioi Bridge in 2015.

• The etched outline of a passerby that was imprinted on the Yorozuyo Bridge after the heat of the bomb. This was 860 metres from the centre of the blast; the asphalt was scorched everywhere except the light area, which was shielded by their body. Today, the bridge has been tiled over.

• Residents walk near Aioi Bridge in Hiroshima, October 1945, and the bridge today.

• People walk past the A-Bomb Dome on the Aioi Bridge. Today, cyclists cross the bridge.

• The shadows of railings cast on the Yorozuyo Bridge road by the heat of the bomb.

• The ruins of Nagasaki Medical College after the second bomb was dropped on Nagasaki, three days later.

• The Urakami Cathedral in Nagasaki, which was obliterated on 9 August. The replacement was built in 1959.

• The south face of Urakami Cathedral in 1945 – and the rebuilt cathedral.

• The ruins of the Shiroyama National School in Nagasaki, and the same road today.

• Two people walk on a cleared path through the destruction resulting from the 6 August detonation of the first atomic bomb in Hiroshima, western Japan.

• A new city rose from the ashes, however, and it is now a buzzing modern metropolis.

• The one-legged rubble of a torii — an archway into a sacred shrine— remains at Sannō Shrine to commemorate the day the city was bombed.