Something there is not accurate. Hiroshima (Little Boy) was around 15 kilotons, and Nagasaki (Fat Man) was around 20 kilotons. A 500 kiloton device is pretty damn big.
Do you perhaps mean "5 kiloton", or was the "500" the number of devices rather than the yield of them?
Anthing bigger than 5 sticks of dynamite is BIG to me, because 5 sticks of dynamite is the largest explosion I have ever seen!
Even 5 kilotons is more than I can vizualize with any accuracy.