Editor's Note: Watch the full report from Martin Savidge on AC360° at 8 p.m. ET.

Sullivan City, Texas is unlike other border towns I've visited. It's one of several towns along the Rio Grande Valley on the southernmost tip of Texas.  People here have a close connection with those across the Rio Grande in Mexico. They are cousins, brothers, sisters, uncles, even parents to relatives on both sides of the border. With family members so close, many have spent generations traveling across the tiny border here to visit the other side.

On the American side, the populations are relatively small. The area consists of dusty towns that line Highway 83 along the border. There is a lot of farm land, some small business and a handful of traffic lights in each town.

We did what very few people have done in recent years.  We took the hand-pulled ferry across the border into Mexico to get a better understanding of the relationship between the two sides.

FULL POST