Two thousand years ago, London was a small village by the River Thames. Then the Romans came and built a town, and thousands of people lived there. Now, in the twenty-first century, London is the biggest city in Britain, with more than 7 million people. It is the capital city of the United Kingdom, the home of Queen Elizabeth the Second, and the home of the British government. Millions of visitors come to London every year. The name 'London' comes from the Romans. Visitors like to see the royal buildings, and sometimes you can go inside them too. Buckingham Palace stands at the end of the Mall. The Mall is a long road, and begins at Trafalgar Square. About 300 people work at the palace, because it is the Queen’s home and her ‘office’. Heads of governments and royal visitors from around the world meet the Queen here. At half past eleven most mornings, the soldiers change the guard at Buckingham Palace. It takes about thirty minutes, and you can stand in front of the palace and watch.