It is very hard to judge this. There is no ultimate answer but if you mean power as in money, then the most expensive city in 2010 has now been changed from Tokyo to Luanda.
The most powerful bomb ever made was the tsar bomb.
Fluorine is the most reactive.
New York City.
It depends if the memory from the caster is happy enough.
Hydrogen bomb is the most powerful bomb
The most powerful water type is Suicune.
wind
No, Athens became the most powerful Greek city-state.
Castle bravo is the most powerful bomb ever IN THE US
NYC.
Taylor Brown
lightning