The Essence of London
The most famous churches in the world are here: St. Paul's Cathedral, Westminster Abbey, St. Martin in the Fields, Brompton Oratory. The tube is a mixed blessing: "There are delays on the Northern Line." London has some of the best and most famous (think "Victoria and Albert") museums in the world - and they're all free. The tourist hordes around Parliament and the Thames are astonishing. You'll be forever yelling "I've been there!" when you see the iconic sites in movies after a trip to London.