My book War at the Top of the World was written to help warn of the manifest dangers coming from this complex, little-known confrontation which is the world's longest running border conflict.
Hundreds of thousands of Catalonians joined hands to form a human chain 250 miles (400km) long, running from the border with neighbouring France to the region of Valencia in a call for Madrid to recognise Catalan independence.
It was a single track, narrow gauge railway and was slightly over 19 mile long running through the rugged and picturesque area bordering Exmoor in North Devon, England.
Long running, quicker running, sharper running.
Jordan and Turkey are also feeling a pressure on their borders with recurrent incidents spilling over from Syria and a refugees' crisis that might have long run repercussions on demographics and borders.
In Mexico, relatively small gangs had long run heroin and marijuana across the border.
They had been used by refugees to bring them to the shelter, fuel for cars having long run out in some of the border areas.
But tensions have long run high in the Eighth Congressional District of Arizona, a classic swing district that shares a 114-mile border with Mexico.
a Short run and b long run.
