Any experienced traveler knows that it's possible to be in two places at once... and sometimes, even three. Some borders are simply metaphorical lines on a map. But other borders provide stark, physical contrasts between one country or region and another.
There are borders that blaze through trees, float on water and even cause roadway mix-ups in their effort to mark the spot where one place ends and another begins. See how it's done around the world.
1. The Netherlands and Belgium
Here, the Belgian village of Baarle-Hertog and the Dutch village of Baarle-Nassau are patch-worked together in little pieces. Travelers cross the international border all the time, and white marks on the ground tell them which country they're in.
2. United States and Canadathe Slash.
3. Poland and Ukraine
This crop design was part of a 2012 art exhibition on the border between Poland and Ukraine.
4. Haiti and the Dominican Republic
Deforestation issues are obvious at the border between Haiti (left) and the Dominican Republic (right).
5. China and Macauspecial administrative region of China, where locals drive on the left side of the road. The rest of China drives on the right, hence the highway changeup at the border.
6. United States and Mexico
At Border Field State Park, a fence separates San Diego, California and Tijuana, Mexico.
7. Argentina, Paraguay and BrazilTriple Frontier, where the Paraná River and the Iguazu River meet.
8. Germany and the Czech Republicdifferent ways of dealing with their pesky bark beetle infestation.