One hiking book my family owns described Spain as the second most mountainous country in Europe. Several online sources claim the same:
After Switzerland, Spain is the most mountainous country in Europe.
it [Spain] is the second most mountainous in Europe after Switzerland.
Wikipedia, Tourism in Spain:
Spain, as the second most mountainous country of Europe, (...)
I've travelled in Spain and there are indeed quite a few mountains. None of those sources define what they mean by most mountainous. I can think of quite a few possible definitions, and although I did not back it up by sources, for all of those I suspect there are at least two European countries that would rank higher:
- Total area covered by mountains? What is a mountain? Probably more in Norway, Sweden, Russia, maybe Switzerland, Austria…
- Fraction of total area covered by mountains? (Again, what is a mountain?) More in Switzerland, Liechtenstein, Andorra, Norway…
- Actual surface area divided by surface area projected onto the geoid (close but not equal to previous one)? See also Is La Palma the steepest island in the world?.
- Number of (ultra) prominent peaks? Switzerland, Austria, Italy have more.
- Number of ultra prominent peaks per unit area?
Is there any (reasonable) definition of mountainous by which Spain is the second most mountainous country in Europe?