The United States' border fence has cost the country $3 billion already, and the massive structure hasn't been a significant deterrent against illegal immigration, according to a recent documentary film.

"The Fence" aired on HBO and aims to show exactly how the wall, approved in 2006, is both a failure and a black eye for US border policy. 

According to Reuters, The Fence argues that both undocumented immigrants, drug smugglers and even terrorists can "easily climb over, dig under" the fence along the border, which, at some points, is only "a few feet high" and lacks razor wire.

One of the most perplexing aspects of the fence is that it ends abruptly in the southwestern desert. 

Another negative aspect of the fence's construction is that it forces undocumented immigrants to find more dangerous routes across the border, which many times results in death.

Immigration experts and the Mexican government estimate that up to 500 people die each year attempting to cross the U.S.-Mexico border, which is a significantly higher number than it was just last decade, reports Reuters. 

Currently, the wall occupies some 650 miles along the border and contains nearly 120,000 tonnes of everything from railroad ties to chain link fence to concrete. Yet the fence has proved woefully inadequate thus far at preventing people from entering the U.S. through its southern border.

Combined with the knowledge that last year, net migration between Mexico and the U.S. was zero, it would seem both U.S. politicians and their constituents alike need to seriously reevaluate how they perceive the so-called "problem" of illegal immigration in this country. 

According to Bloomberg Government, completely sealing the border would cost taxpayers $28 billion per year; that's $16 billion more than is currently being spent on border security right now, and even with that increase in spending, the border wouldn't be secure for another five years. 

It has also been proposed by Bloomberg that a better border policy, one that saves money and is overall more efficient, would be for U.S. border spending to fluctuate along with changes in the rate of illegal immigration.

Yet such policy seems unlikely to be adopted anytime soon as both Democrats and Republican are calling for increasing spending along the border.