With a population of approximately 7.1 million (approximately 13% of the country's
population), London is the largest city in Europe and the 21st largest metropolitan area in the
world (according to http://www.citymayors.com). This may be the only time in your life when
you can pop into the city for a day for just $20, so take advantage of the opportunity while you
have it! That is to say, it's a big place and there is a lot going on. If you decide to visit, this
section can offer a few pointers.

• Traveling into London -
  The quickest and easiest way to get into London is to take the train. A train from Cambridge to
  London "all terminals" (namely, King's Cross or Liverpool Street) will cost about £16 roundtrip
  (or £12 with a railcard) and take 45 to 90 minutes, depending on how many stops there are along
  the way. However, trains leaving before 9 am are considered "peak" and cost more, but as the
  trains are very frequent (more than one per hour), you can avoid the higher prices if your
  schedule is flexible. One option to strongly consider is the One-Day Travelcard, which costs
  about £22 (£14ish with Young persons' railcard). The pass covers the train ride to and from
  London (both journeys must be on the same day) and also gives you unlimited Underground and
  bus travel throughout the day.
  Ask at the train station for a savings booklet if you're planning on touring around London. With
  your train ticket, you'll be able to get a few worthwhile 2-for-1 offers on restaurants, tourist sites,
  and shows. (Though most of them are junk, there are a few good coupons in it.)
  One of the easiest ways to get around London is on the Underground. You can purchase day
  travelcards or individual tickets, both of which must be chosen according to what zones you want
  to travel in. Travelcards work for both the Underground and the buses. (A common choice is a
  day travelcard for zones 1 and 2, which covers central London, at a cost of £4.30 off-peak. For
  more information on fares, visit the London Underground website at http://tube.tfl.gov.uk/ ).
  Zone boundaries and a general layout of the twelve different train lines can be seen on the map
  provided by the following link: http://www.tfl.gov.uk/tfl/pdfdocs/colormap.pdf
• What to Do in London -
  The best way to figure out what there is to do in London is talk to other people. London has
  been called the Artistic, Entertainment, Financial, Musical and Tourist capital of Britain. As
  some dude famously uttered long ago, if you get tired of London, you are tired of life!