The proposal to build a more expansive wall along the US-Mexico border is one of the more repeated vows of the Donald Trump presidency. The argument goes that a physical barrier will, naturally, block would-be migrants from coming to the US. At the same time, other walls already exist — not as easily seen by the wider public. They come in many forms, including no-fly lists and limits placed on certain visas, as well as rising costs and sheer difficulty.
With every type of visa and travel document, there are rules that allow some people in and keep others out. These barriers can exist far from the US border, or deep within the country.
The reality is, these invisible walls can be even tougher to breach than concrete slabs for people who are trying to visit or live in the US, lawfully or not. These are stories about people who come up against these walls and defeat them — or are stopped in their tracks.