Juan comes up to the Mexican border on his bicycle. He's got two large bags over his shoulders. The guard stops him and says, "What's in the bags?" "Sand," answered Juan. The guard says, "We'll

 Juan comes up to the Mexican border on his bicycle. He's got two large bags over his shoulders. The guard stops him and says, "What's in the bags?"

"Sand," answered Juan.

The guard says, "We'll need to check that."

So, the guard opens the first bag and finds... nothing but sand. He’s a little confused but says, "Alright, let's check the second bag."

He opens the second bag and, once again, it’s just sand. The guard looks at Juan and says, "Well, you’re good to go. Have a nice day."

Juan nods, smiles, and rides off.

The next week, Juan returns to the border on his bicycle with the same two bags. The same guard is there. The guard stops him and says, "Let me guess. Sand?"

Juan grins and says, "You got it!"

The guard raises an eyebrow and says, "Alright, you’re free to go."

As Juan rides away, the guard watches him, scratching his head. He mutters to himself, “I swear, that guy’s been crossing this border for years… What is he really smuggling?”

And for the next few months, the guard spends his off-hours in his garage, desperately trying to figure out how Juan keeps sneaking all that sand into the country.

Meanwhile, Juan’s making a fortune… selling sand on the black market.