Looking like an unassuming alley but for the iron gates (and armed guards) that block the entrance, 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—although the current prime minister actually lives in the private apartments above No. 11, because those in No. 10 are too small to house a family. (No. 11 is traditionally the residence of the chancellor of the exchequer, the head of the treasury.) There are no public tours, and you can't get past the wrought-iron gates into Downing Street itself, but the famous black front door to No. 10 is clearly visible from Whitehall. 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; the first wreath is traditionally laid by the Queen.
London, SW1A 1AA, England