I've taken precisely two (2) trips that require a passport. Both were long, multi-country and/or multi-continent journeys. Counting North America and Antarctica (not shown), that's four continents. I decided not to include Ukraine, since I was only technically there: I have a Ukranian stamp in my passport from a visit to a scientific station in Antarctica. Nowadays, I'd need a passport to get to Canada.
You can barely see small place like Andorra (a teeny speck in the Pyrenees) and Luxemberg. I've been to Iceland twice, for a total of about 45 minutes, as Icelandic Airways herded us off the plane into the gift shop and back on.