There are probably a few reasons for that.
I started early, flying to the USA at the tender age of 14 months and never saw a reason to stop travelling.
The main driver is probably my innate curiosity and the desire to learn and thus understand.
I have since also realized that traveling runs in the family. My great-grandfather Philip Jakob Hunkeler went into retirement aged 64 (when gout made writing and playing the organ difficult) and used his newly found time for his main passion: travelling. Even at 80 years he used his GA (train ticket) to criss-cross the country, often down to the Ticino, but also down Italy.
On the map above, I show the countries I have visited (where I have slept at least one night). A few exceptions are Jordan (where I spent a whole day off a cruise, visiting Petra) or Liechtenstein (where I have been but never had to sleep) or the Vatican (where I wasn't invited to stay the night).
Looking at the above, I realize there are quite a few white spots...there's still work to be done.
