A woman rides to the border of Mexico on a bike with two bags of sand. She shows the border patrol agent her papers. After examining her sand bags noticing they're full of sand, he lets her cross the border. The next day she returns to the border on a bike with two bags of sand. She shows the border patrol agent her papers. He examines her sand bags and they're full of sand. He lets her cross the border. This continues for a few days. Question: What was she smuggling? - A bridge measures forty miles long. It can only hold 750 lbs. A truck weighing exactly 750 lbs crosses the bridge. As it reaches the middle, a bird weighing 2 lbs lands on it. Despite the added weight, the bridge did not collapse. Question: Why? - Golden treasures I contain, guarded by hundreds and thousands. Stored in a labyrinth where no man walks yet men come often to seize my gold. By smoke I am overcome and robbed then left to build my treasure anew. Question: What am I? See answer