Patagonia Mountains, Arizona (CNN)Once there was a bustling construction zone here. Now it’s like a ghost town, frozen in time.

Heavy machinery is parked and motionless. Stacks of steel bollards stretch as far as the eye can see. The Trump administration built more than 450 miles of fencing along the US-Mexico border — including hundreds of miles of replacement fencing and 52 miles of construction where there were no barriers before. The wall became a focal point of his presidency, a staging ground for political rallies and a symbol of the administration’s controversial immigration crackdowns. On the campaign trail, President Biden vowed not to build another foot. And he swiftly halted construction once he became President.A big question still hasn’t been answered, months into his presidency: What will happen at sites where construction was underway?Read MoreFencing currently covers 706 miles of the 1,954-mile US-Mexico border. We recently visited four locations along that stretch where wall construction had started, but has been paused since Biden became president.So far, the new administration isn’t saying what will happen next in any of these places. But people who live and work in the area have a lot to say about what they want to see.Here’s what we saw, and what they told us:Stop 1: The view from the end of the roadThis is about as far as the border wall construction got about 15 miles east of Nogales, Arizona, in the Patagonia Mountains. What you see now is a path carved through a pristine desert landscape. It’s a scene that’s all too familiar to environmental activist Laiken Jordahl. A former park ranger, he’s spent the last four years campaigning against the border wall in these remote areas of Arizona. Here’s how he describes the landscape:

"It's kind of a bizarre scene because we've got this huge amount of devastation, this massive swath of land that's been blasted open, and nobody knows what's gonna happen next."

Laiken Jordahl, environmental activist

Customs and Border Protection has said border wall projects went through “Environmental Stewardship Plans” to analyze and minimize the environmental impact, including studies of how wildlife may be affected by the projects.Jordahl says he’s seen enough.

"We want to see these contracts canceled, and we want to see the remaining billions of dollars left in those contracts used to restore and revegetate this beautiful landscape."

Laiken Jordahl, environmental activist

Stop 2: Tire tracks in the dirt, but no activity to be foundAt Coronado National Memorial in Arizona, the tire tracks in the dirt are a reminder of the heavy construction equipment that was here just a few months ago.Back in December, crews were feverishly working to finish erecting a stretch of wall here. Border wall construction presses on in Trump's final daysBorder wall construction presses on in Trump's final daysBorder wall construction presses on in Trump's final daysJUST WATCHEDBorder wall construction presses on in Trump’s final daysReplayMore Videos …MUST WATCH

Border wall construction presses on in Trump’s final days 05:23Now, the roads nearby are a blocked off, so we can’t get close enough to see what they built. But this much is clear: The landscape in the area has already changed dramatically.Stop 3: A scarred mountainside and a half-built wallAt Guadalupe Canyon, construction crews were busy at work the last time we visited. All you could hear were the sounds of heavy machinery, construction crews and explosive detonations blasting into the mountains. Now, it’s eerily quiet.Construction has stopped. And you can see a scarred mountainside, a half-built wall and massive amounts of steel — seemingly abandoned. Now remnants of old steel border barriers are blocking access to the new wall.For Jordahl and other anti-border wall activists, the question is, how do you repair a mountain that now looks like this?

"It is enraging. We have watched thousands of pounds of dynamite be detonated in wilderness areas, in corridors for endangered species, in places where there is not frequent migration from people or smugglers. … They have cut through an entire mountain range to build a small section of wall that to someone in DC was just another mile on the tally."

Laiken Jordahl, environmental activist

Stop 4: A scene one sheriff calls ‘foolish’ In Del Rio, Texas, Val Verde County Sheriff Joe Frank Martinez took us to what’s supposed to be a two-mile stretch of border wall. So far, only a few hundred yards have been built.Construction equipment is still on site. Deep trenches are dug out.

"About January the 24th everything stopped. … To me, it's just — just crazy."

Joe Frank Martinez, Val Verde County sheriff

You can still see the smaller fence that used to guard this stretch of border. And that did the trick, Martinez says. Crime, burglaries and theft went down as the structure rerouted smuggling activity and gave Border Patrol agents more time to respond. But now that this new structure — a taller, 30-foot fence — is half-built, the sheriff hopes it will be finished.

"I just think it's foolish to leave this project as it is. My understanding is that they're going to continue in the near future, but that's yet to be seen."

Joe Frank Martinez, Val Verde County sheriff

And there’s one thing he knows he doesn’t want to see: all the fencing being taken down — an idea some critics of the border wall have suggested.

"If that happens, then we're going to go back 20-30 years, where you're going to get masses of people coming through here. Crime rate in my community will go up, because there's no structure here."

Joe Frank Martinez, Val Verde County sheriff

In one of his first actions as President, Biden ordered a pause on wall construction and called for a review of projects and a plan to redirect funds within 60 days. Customs and Border Protection, in coordination with the US Army Corps of Engineers, says that to comply with the President’s proclamation it’s suspended wall construction projects “except for activities that are safety related.” The 60-day review period ended more than a month ago. But pressed for answers on its border wall plans in recent days, the Biden administration hasn’t said much.”Federal agencies are continuing to review wall contracts and develop a plan to submit to the president soon — it is — it is paused,” White House press secretary Jen Psaki recently told reporters.The administration’s latest funding request to Congress includes $1.2 billion for border infrastructure, but no additional funds for wall construction.

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