The US government is currently shut down because President Donald Trump is demanding billions of dollars to build a wall along the US-Mexico border, and Congress won't fund it.

Of the 1,933 miles along the border, 1,279 miles is unfenced.

Most of the barrier that currently exists, and that the Trump administration has built, isn't the high concrete wall Trump talked about on the campaign trail, and instead resembles a fence.

From western California to eastern Texas, across four US states and 24 counties, the 1,933-mile US-Mexico border criss-crosses arid desert, rugged mountains, and winding rivers.

For 654 of those miles, fencing separates the two countries from each other.

The 7.3 million people who live in the border counties on each side of the line have watched for years as security grew tighter and illegal crossings tapered off.

In just the last 12 years, the US government built the barriers, deployed troops, and started using advanced surveillance technology — all in an effort to tame and control some of the wildest and remotest land in the United States.

In an effort to make good on campaign promises to "build that wall," President Donald Trump has refused to back down on his demand that Congress allocate $5.7 billion for the project, plunging the government into a weeks-long shutdown after Senate Democrats refused to back a spending bill with the wall funding.

Democrats, who now control the House of Representatives, have long opposed Trump's wall and placed the blame for the shutdown on Trump.

The shutdown comes amid controversy over US immigration and border policies, after two young migrant children died in Border Patrol custody last month. The deaths also come on the heels of outrage over the Trump administration's family separation policy over the summer, which split thousands of children from their parents.

With public outrage has growing toward the government's immigration policies, it's worth taking a look at the complexity of the borderlands to understand the daunting task of securing them.

From the Pacific Ocean in the west to the Gulf of Mexico in the east, here's what the entire US-Mexico border looks like.