Japan is to mark the 68th anniversary of the atomic bombing of Hiroshima by the US, the first - ever case of the use of the bomb against human beings, which resulted in the death of thousands of people.Tens of thousands of people, including survivors, victims' relatives, and government officials are expected to attend the annual ceremony at Hiroshima Peace Memorial, commonly called the Atomic Bomb Dome, at 8:15 am on Tuesday (2315 GMT Monday), AFP reported. Hiroshima was devastated on August 6, 1945 after the US B-29 bomber Enola Gay dropped an atomic bomb on the city, killing an estimated 140,000 people instantly or gradually from radiation sickness and cancers. Three days later, another atomic bomb was dropped on Nagasaki, killing more than 70,000. This year's anniversary comes at a time when anti-nuclear sentiment is still strong in the country. A destructive nine-magnitude earthquake and an ensuing tsunami struck Japan’s northern coasts in March 2011, setting off a nuclear crisis by knocking out power to cooling systems of reactors at the Fukushima plant, causing radioactive leaks. The waves from the tsunami, which hit the Fukushima Daiichi nuclear plant 45 minutes after the quake, shut down the backup generators at the facility. The early damage disabled the reactor’s cooling system, leading to meltdown, explosions and radiation leaks. Around 19,000 people died or went missing in the disaster.