London is one of the most charming and welcoming cities in Europe for American families traveling abroad -- historical, friendly, and decidedly British. Here you'll find everything from steak-and-kidney pie to high speed boat rides down the Thames. An intriguing blend of the very old (the Tower of London dates to the 11th century) and the very new (the London Eye, built in 2000 for the Millennium, was so modern some old fogies wanted to tear it down), London is diverse, friendly, and always exciting. Yes, it's notoriously expensive (one of the most expensive cities in the world) but don't let that give you pause: many of the best museums in London are free, children ride on public transit without paying a penny, and the luscious royal parks are also gratis.

London rolls out the red carpet treatment to tourists when the high tourist season begins in early June and many American families choose to visit London during the summer months. Though this means you'll be privy to new exhibits and new happenings, you'll also be fighting crowds, big crowds, to see both the major sights and the more out-of-the-way corners of the city. Prices also tend to rise in the summer, as does the heat. If you can go to London during spring or fall vacation (or, better yet, during the off season when American school children aren't on break -- tell their teachers you'll be "world schooling" for a week), you'll get the best of everything: less expensive airfare, special kids' programming and shows for local children on holiday, and fewer crowds. The sticking point is the weather: in the fall you may luck out and experience Indian summer or you may find that the umbrella and rainboots -- two must-haves in London -- are being used way too often.

The only constant about London's weather is change. Cloudy one moment, the sun can burst through the next. Although it has a reputation for rain, downpours and stormy skies are actually unusual: instead you'll get some drizzle for an hour, which will clear up as if it had never been there, only to be followed by another bout of rain later in the day. But overall the climate is rather mild. From May to October the weather is usually pleasant, highs averaging in the mid 60s during the summer months with lows in the mid 50s (though sometimes, usually in August, the temperature can soar). From September to November, highs are usually in the mid 50s, lows in the mid 40s. Though in recent years the weather has been even more topsy turvy usual, perhaps due to climate change, it is unusual to have snowfall in the winter months, when the average high is about 45, with lows of 35. Interestingly, March has historically been the month with the least rainfall in London.

Two major airports service London: Heathrow, which is about 15 miles from the center of London, and Gatwick, which is about 35 miles from the center of London. The Picadilly Line of the London Underground (also called the Tube) is free for children under 11 and goes directly to Heathrow. This is an affordable, efficient way to get to and from the airport. The Heathrow Express is a more expensive, high-speed, state-of-the-art train that leaves from Paddington Station every 15 minutes and arrives at Heathrow just 15 minutes later. The Heathrow Connect is another train option that costs less than the Heathrow Express and makes several stops. A cab ride into the city takes anywhere from 20 minutes to over an hour, depending on the traffic, and can cost up to 60 pounds. Dot2dot is a shared shuttle service that picks passengers up at their terminal and delivers them to their destination for a maximum price of 19 pounds per person. Their vehicles are allowed to use the bus lanes on the highway, making this an efficient option. Gatwick airport is serviced by the Gatwick Express, which leaves every 15 minutes and arrives at Victoria Station in a half an hour (16.90 pounds per person). The London Underground also services Gatwick and Dot2dot has pick-up service there as well. See more information here.

There are many ways to get around London, including trains, buses, waterbuses, taxis, and by foot. Many of the historic sights are within walking distance of one another and often the walk itself is as pleasant and interesting as the destination; your kids are apt to spot unexpected gargoyles, historic statues, surrendipitous climbing structures, and strange objects floating in the River Thames along the way. Since public transportation is so extensive and free for children (under 11 on the Underground and under 16 on the buses), your best bet is to buy a multi-day travel card or an Oyster Card. Ask the concierge at your hotel or visit any kiosk close to an Underground Station for more information.

• January: London Boat Show
• February: Imagine Children's Literary Festival (Info)
• March: St. Patrick's Day parade
• May: London International Children's Festival (Info)
• May: Covent Garden May Fayre and Puppetry Festival
• June: Trooping the Color (celebration of the Queen's birthday)
• June, July: Wimbledon
• August: Kids' Week at the West End
• November: London Children's Film Festival (Info)

Visit London is the city's official website for visitors.

If you plan to visit several museums, you can buy a London Pass, which offers discounts and easy entry. Another good option for families planning to visit several royal palaces, including the Tower of London, is to buy a historic Royal Palaces family membership, which is for two adults and up to six children, and includes unlimited entry to five palaces. You can also find some great deals and coupons at LastMinute.com.

• More than 7.5 million people live in London. London is the largest city in the European Union, the London public transportation system is one of the most extensive in the world, and Heathrow Airport has more international passenger traffic than any other airport in the world.
• The average person in Britain wakes up at twelve minutes before 7:00 a.m.
• Only 6 percent of all London cab drivers work after midnight and before 7:00 a.m.
• In London potato chips are called "crisps" and French fries are called "chips." A stroller is called a "push chair" or a "buggy," an elevator is called a "lift," and the trunk of the car is the "boot," a bathroom is a "loo" or "WC" and a diaper is called a "nappy."
• Instead of saying "excuse me" when they want to get by, Londoners say "sorry."
• In the 19th century most people in London drank beer with every meal because the water was so polluted it was unsafe to drink.
• The Queen of England, whose full name is Elizabeth Alexandra Mary of York, does not have a passport. Because British passports are issued in Her Majesty's name, there is no need for her to carry one!
• Samuel Johnson wrote famously of London: "You find no man, at all intellectual, who is willing to leave London. No, Sir, when a man is tired of London, he is tired of life; for there is in London all that life can afford."

There are five campground/RV parks in London, which are within striking distance of the city center and accessible by some form of public transportation. For more information, see: visitlondon.com.