It is good to realise that this fast spreading happened in a time, around 1900, that photograpy en the art of printing were in their infancy.
The communication happened mainly by telegraph and correspondence.
It is interesting as well, to see how every country / people found a translation of their own of this spirit of the age so far as architecture is concerned.
The Dutch appearance is generally austere.The Belgian and French buildings are luxurious with round and oval shapes and dynamic motifs. The German appearance is lacking that graze, it feels often static and heavy to me.
In the eastern part of Germany and the Czech republic you will mainly find facades with artistic plaster. The Spanish variant is capicious and more exuberant.
But almost everywhere, there is an application of mosaic work, stained glass, decoratif wrought ironwork, glazed stones and stuccoworks
that give these buildings a characteristic that since then, no other style of architecture has done.