u.s.-mexican borderland.rrator: regions, relative location and scale help us gain a spatial perspective on places like el paso, texas, and ciudad juarez, mexico. the border between the two countries marks the limits of what geographers call "formal regions"-- places with very clear lines. but as you cross the bridge into texas you see that the cultural lines are not nearly as sharp. tanny berg owns some retail real estate on el paso street and plays an active role in the life of the community. berg: this street, particularly, has always been a wonderful threshold, a transition between america and mexico. those of us who are in business on the street, it has always been our intentions to improve the relationships between the united states and mexico-- and, more particularly between el paso and juarez-- because obviously that interrelationship affords us the opportunity of attracting more customers into our market. narrator: but the flow of culture is two-way. berg has shopped at this same mexican bakery since

u.s.-mexican border two hours north of mcallen. >> we've had, along the border, shootings.border, murders, home invasions, burglaries, rapes. all types of crime where it's associated with what i call spillover violence. >> reporter: siggy gonzalez was the sheriff of zap ata county, texas and oversaw the investigation of the hartley incident. he has retired since our interview. >> i remember when i started as a deputy sheriff back in the 1970s, where this was used for drug trafficking. human trafficking. being used like that forever. >> reporter: and lately, even before the hartleys' trip to falcon lake, gonzalez says a new threat has emerged. pirates. >> totally inaccurate. definition of piracy a lot different than what i know it to be. had one robbery on the lake totally. >> reporter: robert speedy colette who owns a fishing lodge here admits he's been stopped by drug cartel members but he also bristles at news reports of piracy and danger. these reports have decimated his business on the lake, which he insists is safe, as long as you know the rules. >> it happened to me.