3 Best Sights in Westminster, London

The Palace of Westminster, as the complex is called, was first established on this site by Edward the Confessor in the 11th century. William II built a new palace in 1097, and this became the seat of English power. A fire destroyed most of the palace in 1834, and the current complex dates largely from the mid-19th century. The best view is from the opposite (south) bank of the Thames, across Lambeth Bridge. It is most dramatic at night when lighted green and gold.

The Visitors' Galleries of the House of Commons provide a view of democracy in action when the benches are filled by opposing MPs (members of Parliament). Debates are formal but raucous, especially during Prime Minister's Questions (PMQs), when any MP can put a question to the nation's leader. Tickets to PMQs are free but highly sought after, so the only way for non–U.K. citizens to gain access is by lining up on the day and hoping for returns or no-shows—expect to wait for up to two hours, with no guarantee of entry. The action starts at noon every Wednesday when Parliament is sitting, and the whole shebang is broadcast live on television. For non-PMQ debates, embassies and high commissions have a quota of tickets available to their citizens, which can help you avoid long lines. The easiest time to get into the Commons is during an evening session—Parliament is still sitting if the top of the Clock Tower is illuminated. There are also visitors galleries for the House of Lords.

The Clock Tower—renamed Elizabeth Tower in 2012, in honor of Queen Elizabeth II's Diamond Jubilee—was completed in 1858, and contains the 13-ton bell known as Big Ben. At the southwest end of the main Parliament building is the 323-foot-high Victoria Tower. The King uses the Sovereign's Entrance, at its base, when visiting Parliament. 

Engaging guided and audio tours of Parliament are available on Saturday and weekdays when Parliament isn't sitting.

Were it not for the wrought-iron gates and armed guards that block the entrance, you'd probably miss this otherwise unassuming Georgian side street off Whitehall—but this is the location of the famous No. 10, London's modest equivalent of The White House. The Georgian entrance to the mid-17th-century mansion is deceptive; it's actually a huge complex of discreetly linked buildings. Since 1732 it has been the official home and office of the prime minister—the last private resident was the magnificently named Mr. Chicken (the current prime minister actually lives in the private apartments above No. 11, traditionally the residence of the Chancellor of the Exchequer, the head of the Treasury). There are no public tours, but the famous black front door to No. 10 is clearly visible from Whitehall. Keep your eyes peeled for Larry the cat, whose official title is Chief Mouser to the Cabinet Office.

Just south of Downing Street, in the middle of Whitehall, is the Cenotaph, a stark white monolith built to commemorate the 1918 armistice. On Remembrance Day (the Sunday nearest November 11), it's strewn with red poppy wreaths to honor the dead of both world wars and all British and Commonwealth soldiers killed in action since. A hundred yards farther, toward Parliament, is the Monument to the Women of World War II. The prominent black-marble sculpture uses a string of empty uniforms to symbolize the vital service of women in then-traditionally male jobs during the war, as well as in frontline roles, such as medics and auxiliary officers.

The highest court of appeal in the United Kingdom is a surprisingly young institution, only having heard its first cases in 2009. Visitors are welcome to drop by and look at the three courtrooms, housed in the carefully restored Middlesex Guildhall, including the impressive Court Room 1, with its magnificent carved wood ceiling. Court is usually in session Monday through Thursday, and since space in the public galleries is limited, you'll want to arrive early. The Court's art collection, on permanent display, includes portraits by Thomas Gainsborough and Joshua Reynolds. Guided tours are available on Friday at 2 pm. There is a café downstairs.