Salmon

Every year, millions of salmon swim from the ocean into the mouths of rivers and then steadily up the rivers. Passing through waters, around rocks and waterfalls, the fish finally reach their original streams or lakes. They dig out nests in the riverbed and lay their eggs. Then, exhausted by their journey, the parent salmon die. They have finished the task that nature has given them. Months, or years later, the young fish start their trip to the ocean.