I recently got my low flying permit from the Swedish Volunteer Air Corps (Frivilliga Flygkåren — FFK). Now I can legally fly down to 150’ AGL during FFK operations. You get a whole new perspective at that level…
FFK (http://ffk.se/om-ffk/vac-the-volunteer-air-corps) is a licensed aerial work operator with special permission to use (unpaid) PPLs, mainly recruited from flying clubs. Its purpose is to be a resource to the defense (both military and civil) and society in general in disaster/public emergency situations. The most common types of operations are forest fire watch and sea border surveillance.
Is there anything like this in other European countries?
Yes.
In the first years after getting my license, I almost ended up flying for them, but then figured out that it was not for me. Investing lots of time (you can’t just go there, fly and go home) just to build hours – no, thank you.
Yes. http://www.flytjenesten.net
I am flying there, but the “hours” are not particularly compatibible with work and life, so I have not yet been to any missions. Can only operate to 500 feet though 
As it is organised here, it is an interesting concept. The closest you get to a multi crew operation with a PPL. We fly with one pilot. One spotter, and one mission leader.
Very interesting. Probably not available to visiting pilots though?
Apart from this example, the only country I know of where low flying is officially encouraged is NZ where there are special low flying areas from 500’ to the surface. It’s a requirement for PPL issue in NZ and formal low flying training (2 Hrs I think) forms part of a 5Hr ‘terrain familiarisation’ component. Yet another reason to fly NZ! (or Sweden!).
Go somewhere isolate in Scotland before December and enjoy some spectacular low flying.
Or get an instructor’s rating and practise forced landings with your students.
Yet another reason to fly NZ!
Or South Africa. Instructors there seem to be very fond of low flying. We flew slightly above the treetops, and when I wanted to climb because of an upcoming village (to make a bit less noise), I was accused of being afraid to fly low…
Ah yes, South Africa…
Or anywhere in a remote(ish) corner of the US. The 500ft in FAA-land are from any ‘person, livestock, structure or vessel’. In the open desert you can go down to 10 ft if you like. IIRC, same in Namibia and Australia, not that many people would see and report you in these two places anyway 
That was always the case in the UK, too.
I recall reading that EASA ended it, but I don’t know if that’s currently the case.
PPL instructors were unhappy because they could not do PFLs below 500ft anymore.
I recall one instructor I had (the one with a fake ATPL) telling a story that somebody was flying low over the open sea and below the surface was a submarine which saw him, and he got prosecuted Obviously the story was false – like most of his stories. We was well known in the area but vanished from aviation about 10 years ago.
