The Houses of Parliament, along with their trademark clock tower, Big Ben, are the ultimate symbols of London. They're the strongholds of Britain's democracy, the assemblies that effectively trimmed the sails of royal power. Both the House of Commons and the House of Lords are in the former royal Palace of Westminster, which was the king's residence until Henry VIII moved to Whitehall. The current Gothic Revival buildings date from 1840 and were designed by Charles Barry. (The earlier buildings were destroyed by fire in 1834.) Assisting Barry was Augustus Welby Pugin, who designed the paneled ceilings, tiled floors, stained glass, clocks, fireplaces, umbrella stands, and even the inkwells. There are more than 1,000 rooms and 3km (2 miles) of corridors. The clock tower at the eastern end houses the world's most famous timepiece. "Big Ben" refers not to the clock tower itself, but to the largest bell in the chime, which weighs close to 14 tons and is named for the first commissioner of works, Sir Benjamin Hall.

You may observe debates for free from the Stranger's Galleries in both houses. Sessions usually begin in mid-October and run to the end of July, with recesses at Christmas and Easter. You line up at Stephen's Gate, heading to your left for the entrance into the Commons or to the right for the Lords. The London daily newspapers announce sessions of Parliament. The chances of getting into the House of Lords when it's in session are generally better than for the more popular House of Commons. Although we can't promise you the oratory of a Charles James Fox or a William Pitt the Elder, the debates in the House of Commons are often lively and controversial (seats are at a premium during crises).

For years, London tabloids have portrayed members of the House of Lords as a bunch of "Monty Pythonesque upper-class twits," with one foreign secretary calling the House of Lords "medieval lumber." Today, under Tony Blair's Labour government, the House of Lords is being shaken up as lords lose their inherited posts. Panels are studying what to do with this largely useless house, its members often descendants of royal mistresses and ancient landowners.

Those who'd like to book a tour can do so, but it takes a bit of work. Both houses are open to the general public for guided tours only during July and August. During those times, the palace is open Monday through Saturday from 9:30am, with the last entry at 4:15pm. All tour tickets cost £7 ($11) per person. You need to send a written request for a tour to the Public Information Office, 1 Derby Gate, Westminster, London SW1A 2TT. The staff is prompt in replying, but only if you include a stamped return envelope (international postage only). Tickets can also be booked through London's Ticketmaster (tel. 020/7344-9966; www.ticketmaster.co.uk).

Insider's Tip: The hottest ticket and the most exciting time to visit is during "Prime Minister's Question Time" on Wednesdays, which is only from 3 to 3:30pm, but which must seem like hours to Tony Blair, who is on the hot seat. It's not quite as thrilling as it was back when Margaret Thatcher exchanged barbs with the MPs (members of Parliament), but Blair holds his own admirably against any and all who try to embarrass him and his government. He is given no mercy from these MPs, especially those who oppose his policies.

Across the street is the Jewel Tower, Abingdon Street (tel. 020/7222-2219), one of only two surviving buildings from the medieval Palace of Westminster. It was constructed in 1365 as a place where Edward III could stash his treasure trove. The tower hosts an exhibition on the history of Parliament and makes for a great introduction to the inner workings of the British government. The video presentation on the top floor is especially informative. A touch-screen computer allows visitors to take a virtual tour of both houses of Parliament. The tower is open daily from 10am to 6pm April to September; 10am to 5pm in October; and 10am to 4pm November to March. Admission is £1.60 ($2.55) for adults, £1.20 ($1.90) for students and seniors, and 80p ($1.30) for children.