Just a month ago, I finished another demanding travel challenge together with three friends. We have been on a tour around Germany, to log at least 10 caches in each of the 9 neighbour countries within 8 days (GC53CYB Challenge-Wald IX - Rund um Deutschland (8/9/10) http://coord.info/GC53CYB.
I can tell you, we really enjoyed this trip!
Of course, we also visited Liechtenstein, as it was on our way (and necessary for another challenge ).
When we reached Austria, we thought spontaneously about doing 5 countries a day the next day. We had to add a cache in France, as the visit in France was initially planned a day later, but that was all, we had to prepare. A similar challenge in Germany near Trier even demands that the five caches must be from a different type and from different years of hiding.
Here is an excerpt of our list of findings from 18th of August 2015, which fulfills the demands:
Austria: GC2E2XG airmail (Letterbox, hidden 26/08/2010) http://www.geocaching.com/seek/log.aspx?LUID=60e8556d-153c-4d93-a9b7-5d095623fdac
Liechtenstein: GC4Y77P FC Ruggell (Mystery, hidden 07/02/2014) http://www.geocaching.com/seek/log.aspx?LUID=4ca9635c-e36b-4d34-a058-8af48f4ccf55
Switzerland: GCQG6D LSZX (Webcam, hidden 09/09/2005) http://www.geocaching.com/seek/log.aspx?LUID=d1db5244-24bb-4ca5-a809-ac22c11fdfde
France: GC48PD2 Le Château d'eau (Tradi, hidden 30/03/2013) http://www.geocaching.com/seek/log.aspx?LUID=25b9a534-2e1b-43c8-9d9c-9d525ad43ea1
Germany: GC1VTTN Der südwestlichste Cache Deutschlands (Multi, hidden 12/07/2009) http://www.geocaching.com/seek/log.aspx?LUID=e911ee79-a134-414b-bce5-b79ebae6ce70
If you think, webcams are too virtual (although we have a photo as logproof ), here is another cache of ten or eleven, we logged in Switzerland the same day:
GC2F085 Die verflixten Lugipfüpfe http://www.geocaching.com/seek/log.aspx?LUID=79714292-7a9d-451c-a053-80b74d8b5e88
I found the final after a business date in Harelbeke. A nice little climber. TFTC and greetings from Germany!