Northern Europe
We loved our travel in Northern Europe. Between Jeff and I, we have visited this area several times, the longest travel segment being seven weeks. We naturally find it easy to travel in the United Kingdom and Ireland, as they are both English-speaking.
Using the United Nations Geoscheme, we have segmented the European continent into four groups. Northern Europe includes the Aland Islands, Denmark, Estonia, Faroe Islands, Finland, Guernsey, Iceland, Ireland, Isle of Man, Jersey, Latvia, Lithuania, Norway, Sark, Svalbard and Jan Mayen, Sweden, and United Kingdom (Great Britain and Northern Ireland).
Independently, we have travelled to more countries, but together we have only been to three of the countries on this list: Ireland, Norway, and the United Kingdom.