Henry Lopez took his son Mario to the zoo. Mario loved animals. Henry thought the zoo would make his son happy. Instead, Mario was very angry. "What's wrong?" asked Henry. "All the animals look so sad," said Mario. "They want to be free, not stuck in cages." Henry was surprised. He looked at the tiger in the cage. Mario was right. Henry had never noticed how sad all the animals looked. By the time Henry looked down at his son, Mario was gone. Suddenly, Henry heard a lot of people yelling. Mario then came running proudly. "Don't worry, Dad!" he said. "I opened the sad lion's door.