An interesting topic I was just discussing with my brother. What country borders have you come within 10 miles of, on land? (Crossing it counts, obviously). It doesn't count if you're on a plane. To my surprise, I've only actually been to three such boundaries:
France-Netherlands (on St. Martin)
What about you?
I've crossed the US-Mexican border at about 7 places, the US-Canada border at 4 points, the Mexico-Guatemala border at 2 points, the Netherlands-Germany border at 2 places, and the following land borders at least once: Guatemala-Belize, Belize-Mexico, Guatemala-El Salvador, Guatemala-Honduras, Panama-Costa Rica, Peru-Bolivia, Germany-Denmark. I know that I've been within ten miles of the East-West border in Germany, when it existed, and within ten miles of the China-Hong Kong border, when it existed. I've probably been within ten miles of several borders as well, such as the northern and southern borders of Nicaragua, and some of the western borders of Germany, but that's all I can remember at the moment.