What Makes It Bizarre?
While it is a huge stretch of land, that’s not really what makes it bizarre. Not even the fact that it’s unprotected makes it all that strange; there are big, undefended borders in lots of places, although it’s getting rarer all the time.
In order to understand why the border is so weird, we need to go back in time to see how it was created.
Source: The Canada-U.S. Border