What single military event drastically reduced Spain's military power and opened the door for other nations to colonize in the Americas?

The single military is none I hope you get it right it should be 0 .I think that is the answer I hope you get it right

Ifound this on google “the existence of agglomeration economies is central to the explanation of how cities increase in size and population, which places the phenomenon on a larger scale. the concentration of economic activity in cities is one reason for their development and growth.” i hope this you for what your looking for.