The Houses of Parliament building can be found in Westminster, the center of London. Actual tours of Parliament are only available during the summer, but throughout the year visitors can come and watch a committee, debate, or judicial hearing when they are in session. Parliament is divided into a House of Commons and a House of Lords, which occupy two different sections of the building, and the two don't usually intermix. The Lords' Chamber is decorated in all red and has a throne where the monarch can sit if he or she desires. In front of the throne is the Woolsack, which represents the importance of the wool trade. The Commons Chamber is where most of the important governing is done, and the sovereign is not allowed inside unless invited, showing the power of the people in England. The Green benches are divided down the center of the room into the leading party on one side, and all the opponents on the other side. The benches are famously positioned just over two sword lengths apart.
The Houses of Parliament are home to England's greatest historical moments. Look at the floor while in the oldest section of Parliament (Westminster Hall), and you'll find the sight where King Charles I was condemned to beheading and was the first and only English monarch to be executed. It is where the trial was held for the conspirators in the Gunpowder Plot to blow up Parliament. It is where Spencer Perceval was shot and killed, and he remains the only prime minister to be assassinated, as well as many more historical events.
When Parliament is sitting, a flag flies over the Victorian Tower. At night, a light on top of the clock tower indicates it. The story says that the Queen wanted to know that her Parliament was still hard at work at night and could only see the clock tower (and not the rest of Parliament) from Buckingham Palace.