In the capital city of the United Kingdom, London, stands an iconic structure - the Elizabeth Tower, commonly known as the Big Ben. This landmark enjoys a global reputation and is also a symbol of the power and tradition of the British monarchy. Nowadays, the Big Ben has become a popular tourist destination, attracting millions of visitors from around the world each year. However, perched atop the 316-foot-tall Big Ben are some modest pennies, each less than 30 millimeters in size. Why, you might wonder? Well, these pennies play a critical role - without them, the Big Ben would not be able to function properly! Now, let's explore their secrets together.