The world still struggles to fully understand the hellish events in Hiroshima, Japan, on August 6, 1945, after a U.S. warplane dropped the most powerful weapon ever produced on military targets and unsuspecting civilians.
Those who survived say it started with a brilliant, noiseless flash. They remember a massive wave of intense heat that turned clothing to rags. People closest to the bomb were immediately vaporized or burned to ashes. There was a deafening boom and a blast that -- for some -- felt like being stabbed by hundreds of needles.
Then the fires started. Tornadoes of flames swept through the city. Many survivors found themselves covered with blisters. Bodies littered the streets.
It got worse. It began to rain. Sticky, radioactive raindrops blackened everything they touched and were hard to wash off.
It's estimated that at least 70,000 people died in the hours immediately following the blast. Later, radiation sickness, cancer and other long-term effects pushed the estimated death toll above 200,000, according to the U.S. Department of Energy
But many survived and are still alive today. As of March 2014, Japan counted 192,719 people as registered survivors, according to the news network Asahi
. The Hiroshima Peace Memorial Museum
has collected thousands of survivors' stories and their drawings, along with artifacts from the blast.
The drawings depict haunting memories. In one drawing, a mother is screaming her child's name while looking down at a river full of dead children.
Another rendering shows a pair of students with swollen blue faces.
An exodus of wounded survivors is depicted in another drawing. They're seen packed into rail cars like cattle.
Each drawing reveals glimpses of that horrific day, reflected through the prism of a survivor's personal struggle to stay alive.
The artifacts range from the poignant to the bizarre: a blackened Shirley Temple doll brought from America, a clump of coins fused together by the blast's intense heat.
The story behind one artifact was published as a children's book by survivor Tatsuharu Kodama in 1995. "Shin's Tricycle"
tells what happened to a 3-year-old boy named Shinichi Tetsutani.
It's narrated by Shin's father, Nobuo Tetsunani, who describes the morning shortly before the attack as a calm and sunny day. "The air was filled with the sandpapery sounds of cicadas rubbing their legs together in the nearby trees," the book said.
Shin and his best friend, a girl named Kimi, were outside the family's home, playing with his favorite toy -- a tricycle with red handlebars.
At 8:15 a.m., the bomb detonated. And everything changed.
The blast collapsed the house, creating an "explosion so terrible, a flash so blindingly bright. I thought the world had ended," the boy's father said in the book. "Then, just a quickly, everything went black."
Shin was missing in the chaos immediately following the attack. His family frantically searched for him among the wreckage of his destroyed home. They found Shin pinned under a house beam, badly hurt. "His face was bleeding and swollen," the book reads. "He was too weak to talk but his hand still held the red handlebar grip from his tricycle. Kimi was gone, lost somewhere under the house."
The family joined other neighborhood survivors along a nearby riverbank. "It was a horrible sight," the book said. "Everyone was burned, and they were crying moaning and screaming for water."
"'Water, I want water,' pleaded Shin in a faint voice. I wanted to help him so much," his father said in the book.
"All around, people were dying when they drank water," Shin's father said. "So I didn't dare give him any."
Shin would not survive the night.
After his son died, Shin's father couldn't bare to leave the boy's body in a lonely graveyard. So the family buried Shin in their backyard, along with his friend Kimi and his beloved tricycle.
In 1985, 40 years later, Shin's father decided to move his son's remains to the family gravesite. He and Kimi's mother helped unearth the backyard grave. There, according to the book, they saw "the little white bones of Kimi and Shin, hand in hand as we had placed them."
Shin's father had all but forgotten about the tricycle. But there it was.
Lifting it out of the grave, he said: "This should never happen to children. The world should be a peaceful place where children can play and laugh."
The next day Shin's father donated the trike to the museum.
There, the legacy of a 3-year-old boy continues to remind future generations of the horrors of nuclear destruction.