My first thoughts
Laredo is in Texas, the biggest city of the Webb county. If the word Texas brings in your mind a picture like this, then I warn you that it is history! Laredo is a modern quiet city that would have almost nothing if it was not the main GATEWAY to MEXICO. Laredo is not at all a typical US city. It happens exactly the opposite. Laredo is a "special case", and this "peculiarity" is making it an interesting place to visit.
@ I could not imagine that I would find US citizens not speaking English!
@ I was not aware that it would be so simple to enter on foot in Mexico just for some hours and get back so easily!