A giant border wall between the US and Mexico? Here are five images that show how complicated that would be.

Writer Cecilia Balli remembers the first time she saw the US-Mexico border fence, the built-up version of it in South Texas in 2008.

“When I first drove by it on the way to my uncle’s house, it shocked me. It’s desolate land. To me, it’s very beautiful land. I’m from here. I’m very rooted here, and all of a sudden I see this 18-foot steel fence. It looked like a scar, like a cut that’d just been sutured.”

A lasting memory, but one that Balli realized many people had where she grew up in Brownsville, in the Rio Grande Valley, at the southernmost tip of the state. It’s less than a mile from Mexico’s border. “People will tell you about the impact that they felt, the emotional force that seeing the fence for the first time had on them.”

The fence is personal for Balli, her parents grew up on the Mexican side of the border, but her perspective is also rooted in studying the history, politics, the people and realities that that fence — and the proposal of expanding it — represents. The obstacles are many, from concerns about environmental damage and areas of the border that run through Indian reservations — to the billions it would cost. There's also the question of homes that the fence slices through.

“A lot of the border, especially in South Texas, runs though private property. I think Americans from a distance imagine the border as being this uninhabited, desolate place that belongs to the government.”

In this image, we see one landowner's property near Brownsville, is bisected by the fence — even though all of his land is in the US. The fence runs inland, about a mile away from the Mexican border. "The horse is on the other side of the fence from its barn because the owner moved it there to graze," writes Balli.

Michael Dear, a professor in the College of Environmental Design at the University of California, Berkeley, is another longtime observer of the border. In his new book, "Why Walls Won't Work," he writes about the history of the border and its build up over the years, especially after Sept. 11.

Here we see a renovated downtown Nogales, on the US side, and a pedestrian-only border crossing. "The fence was modified as a consequence of community pressure to ensure visual contact through to the other side," Dear says. Meanwhile, the fence has grown taller and, in some parts, the National Guard and private contractors have been employed to attach chain-linked additions.

"In Arizona, the physical and social topography changes," Balli writes. "There, the fence runs literally along the borderline. Private ranchers own long stretches of land along it, and there are some twin border cities (Douglas and Nogales among them)."

"But there are also miles and miles of pristine state and federal parklands. Seeing the fence there takes your breath away, in a confusing way. This image was taken from the Organ Pipe Cactus National Monument. The left side of the fence is Mexico. When I first saw the fence here, it struck me that it looked like a fresh scar on the land, a deep wound messily sutured up. It made me think of South Texas writer Gloria Anzaldúa's line about how the US-Mexico border is an open wound."