Great Britain, United Kingdom or British Isles it would seem almost if there was an identity crisis here. Great Britain sounds pretentious but it defined the difference between little Britain that was supposedly Brittany in France when the English kings did not know on which side of the sea they wanted to be.
Britain has a full and interesting History dating from 10,000 years. Bronze was manufactured and traded from a very early time and in the north there are newly explored copper mines.
However today I will deal mainly with London. Relatively speaking London is New only becoming a major settlement about 2000 years ago.
The Romans built extensively in the city part of London. There are excavations around Tower Hill near to Tower Bridge that can be seen easily entering some of the underground railway stations.
London is in fact two cities, the city of London and the City of Westminster. On top of that there are 32 Boroughs of which two are Royal Boroughs. The Royal Boroughs have Palaces such as Buckingham Palace and Hampton Court.
Although the city is the commercial and financial centre there are numerous banks etc at Canary Wharf, this was a development of , for UK high rise buildings. They are built in former docklands area and are to the East of the City, and North of Greenwich.
Let us Stat with the City of London, often called just the City. It is about one square mile and there are over 700 hundred banks registered in the city. Some just have a representative office there.
For the Tourist the main sites are Tower Bridge and The Tower of London. They have a similar appearance architecturally but were built almost a thousand years apart. Tower Bridge is, a typical English thing, registered for insurance purposes as a ship. The Roadway is lifted when ever a ship, etc needs to pass underneath the roadway and the two spans weigh 1000 tons. The bridge was completed in 1894.
On The North of the River You will find to the west of Tower Bridge the Tower of London. The full name is 'Her Majesty's Royal Palace and Fortress the Tower of London' this was Started by The Norman Invaders in 1078. They invaded and conquered England in 1066, the last successful invasion of England, although others have tried non succeeded since. It was expanded and developed over the centauries but the central part is of considerable age. In 1240 The King made it a palace and his home. Henry the V111, the one of many wives had those who he wanted ride of imprisoned there and some executed there, nice fellow.
In more modern times, German spies were executed in the courtyards during the two World Wars, and in 1941, Hitler's deputy - Rudolph Hess, who some say was a trifle odd and flew uninvited at the height of the war to try to persuade the British that Hitler was not all bad was actually imprisoned in the Tower.
The Jewel House is where you'll find the Crown Jewels, a collection of gold, silver and , precious stones
Two permanent features are the Ravens flightless birds, which by superstition by their continued residence ensure the safety of the British Commonwealth. and Beefeaters
I would suggest a visit to :- http://www.hrp.org.uk/

Every tourist must get to the Tower of London at least once. Beside the crown jewels, the history of the Tower, beginning with the Normans is compelling. There are ongoing guided tours, and jolly Beefeaters tell stories of beheadings and torture.
This past summer, at Oxford, I took a course entitled.Archeology of Medieval Palaces in England. The tutor, an archeologist, is currently part of an exploration in/of the moat that surrounds the palace.Simply fascinating.
Tourists also need to know about the half price theatre tickets at Leisester (sp?) Square, the National and Portrait galleries and St Martins in Trafalger Square and where there is an outlet store for Burberry.If I wasn't living in NY, I would be live in London.
On Saturday in Covent Gardens, there are jugglers and mines, and stuff and more stuff for sale. For the ladies, check out Zara, in the indoor shopping part, for lovely hand made sweaters, priced very well.