J. Robert Oppenheimer was made the director of the Los Alamos lab in 1943, he then gathered 200 of the best scientist in the field to live and work there. They designed two bombs named "Fat Man" and "Little Boy", Fat Man used plutonium and Little Boy used uranium
On August 6, 1945, during WWII (1939-1945), an American B-29 bomber dropped the worlds first deployed atomic bomb over the Japanese city of Hiroshima. The explosion wiped out 90% of the city and immediately killed 80,000 people; tens of thousands more would later die of radiation exposure.
Though exposure to radiation can cause acute, near-immediate effect by killing cells and directly damaging tissue, radiation can also have effects that happens on longer scale, such as cancer, by causing mutations in DNA of living cells.
By the time spring of 1946 arrived, the citizens of Hiroshima were surprised to find the landscape dotted with the blooming red pedals of the oleander. The oleander flower, called the "kyochikuto" in Japanese, took away worries that the city had lost it fertility and inspired the population with hope that Hiroshima would soon recover from the tragic bombing.