“Poor Niagara!” said Eleanor Roosevelt (reportedly) upon seeing Iguazu Falls, a series of waterfalls stretching for a mile and a half between Brazil and Argentina. We recently visited the Brazilian side of the falls and enjoyed lingering along the trail, captivated by the magnitude and splendor of so many cascading rivulets amidst so much green forest.

As we meandered, I often stopped to watch a particular ripple of water glide, hover, and crash down into the river. I enjoyed how the water seemed to move both quickly and slowly at the same time. I noticed sections of the cliffs where little islands of grass and trees separated the flat horizontal plane of the river from the sheer vertical drop of the falls, distorting my sense of what was land and what was water.

These various blurrings got me thinking about borders we’ve encountered lately: between city and country, between Spanish…