Any conversation of the five or so greatest cities in the world automatically includes London. Whether you are talking about leading financial centres, cultural, educational, political, or entertainment centres, doesn't really matter. London will be mentioned as a leader in these and many more categories.

The population of London is quite diverse, and an estimated 300 different languages are spoken by its inhabitants. Those inhabitants number about 7.5 million, in the city and boroughs, and a total of 12 to 14 million in the metropolitan area combined. This ranks the London metro area at 18th in the list of the largest world metropolitan areas.

London was the largest metropolitan area in the world by population from 1825 to 1925, but has been overtaken by many cities around the world, and probably just as well. The diverse population is a lesson in tolerance, with 30 % of the population being born outside the U.K. Perhaps it's not so much tolerance as apathy. Londoners are not known for their warmth towards foreigners, but London is a place of business and it is necessary to get along to do business.

Certainly no one could blame Londoners for feeling a little distain towards its immigrant population, but they really don't. London has long been a target of terrorist attacks of one kind or another. Without going too far back into history you can try imagining what it would have been like to be raising children during the early part of the 20th Century when World War I had Zeppelins overhead dropping incendiary bombs on the city. This was one of the earliest aerial bombings ever, and it took a while before defences were developed to combat the bombing.

World War II was even worse, when the German Blitz had the population in constant fear, bombing the city day and night. In both situations, much of the population headed for the countryside, or at least sent their children there. Several decades later car bombs were detonated and pubs were targeted. Other attacks took place in the city by Provisional IRA and other groups sympathetic to their cause over the last four decades. The newest, most recent attacks by Muslim Extremists on public transportation systems would cause many countries to close their borders, and take an isolationist stance, but Londoners seem to know the difference between Muslims and Muslim extremists, and don't show fear or distain for any of these groups, or others who have attacked them over the years. They don't roll out the red carpet, but they show a genuine open mindedness toward most people. They also show a logical approach to dealing with terrorism.

It may be that dealing with harsh reality gets easier over time. London has endured Plague, Civil War, Devastating Fires, along with bombardment and attacks over the past two thousand years, and seems to come back stronger from each event.

Throughout all of this London has remained one of the most diverse cities in the world.

London has also remained a vibrant city and a leader in all of the categories of any importance that makeup a key global city.

London has thirty two boroughs, and the city of Westminster included within its loosely organized boundaries. Over time boroughs have been grouped into districts, cities, and other authorities in many different and sometimes confusing ways. Talking about Central London, Inner London, Greater London, The City of London, Metropolitan London, Municipal London, or Outer London is quite confusing to anyone who hasn't spent a lot of time there.

Having a map on hand may be a requirement for not only tourists, but residents as well.

The actual City of London is a small city within Greater London. It is the core of London and not much bigger than a square mile. This area of the city is the major financial centre, and is Europe's second largest central business district.

Besides being a powerful financial community, London is also a great transportation hub. London has five international airports, and is a large port. Heathrow International Airport alone carries more passengers than other airport in the world.

Also a great tourist destination, London offers entertainment with theatre, music, dance, and films. Shopping is a big draw to people visiting London with many famous shopping venues. From small markets to huge department stores many people are attracted to London by the shopping opportunities.

Clubs and live music venues bring in another crowd, albeit a little different crowd, but again London is all about diversity. Sports, attractions, cultural spots, and historic locations also bring in tourists by the car load. Buses are a primary method of touring London, but a ride on British Airway's London Eye gives you a good look at the city from the banks of The River Thames and on a clear day you can take in 55 of the most famous landmarks in London in a half hour ride on the Eye. This can be combined with a river cruise that departs from LondonEye Pier to get an even more detailed look at the sights. It's a good idea to do this at the beginning of a sightseeing journey because seeing the sights from the Eye may help you decide which ones you want to see in person and give you an idea of their location from where you are staying.

London has some great museums, and you can gain access to many of them without breaking your budget. The National Gallery displays many classic paintings, while The National Portrait Gallery displays portraits of many of history's most famous people. The National Portrait Gallery also has a rooftop restaurant with great views. The Tate Britain, and Tate Modern Galleries are excellent, and The Royal Academy of the Arts has been putting on a great summer exhibition since 1768.

The Tower of London where The Crown Jewels are kept, Tower Bridge, St Paul's Cathedral, Buckingham Palace, and Royal Albert Hall are other must see landmarks that will help you gain an understanding and an appreciation of London's history.