A nuclear bomb dropped by Iran on Israel -i Tulsi Gabbard recenlty said about the destruction:

. . . one bomb that caused so much destruction on Hiroshima was tiny compared to today’s nuclear bombs. The bomb that was dropped on Hiroshima had a yield of just 15 kilotons of TNT. Whereas today’s nuclear warheads range in size from 100 kilotons to over 1 megaton, a single nuclear weapon today could kill millions in just minutes. Just one of these nuclear bombs would vaporize everything at its core, people, buildings, life itself. The shockwave would crush structures miles away, killing and maiming countless people.

And then comes the fallout. Radioactive poison spreading through the air, water, and soil, condemning survivors to agonizing deaths or lifelong suffering. A nuclear winter could follow with smoke and ash completely blocking the sun, plunging the world into darkness and cold, killing crops and starving billions. Acid rain would scar the earth, wiping out entire ecosystems.