Off to Europe : Young Tour Leader Loose in London : An 8-year-old pursues his own interests in the British capital, educating himself and a grown-up.

LONDON —  Across the road from Windsor Castle, just west of London, 8-year-old Matt had his choice for an afternoon snack: a traditional English tea, McDonald’s or Pizza Hut.

Forget tea. He chose McDonald’s--along with a bunch of boys from nearby Eton College, Britain’s most famous private school that dates from 1440.

Matt and the boys, young teen-agers decked out in American sports team caps and sweat shirts, exchanged shy smiles between bites of burgers and fries. “They look just like American kids,” Matt decided.

Later, we walked down the narrow cobbled road to Eton’s famous buildings. “Kids were going to school here before Columbus came to America,” Matt mused.

He had had a similar reaction earlier, as we toured sprawling Windsor Castle (we were there shortly before the November fire destroyed some of the rooms). The largest castle in the world where royalty still lives, it’s just a short train ride from London. “This is a lot bigger than the White House. Do you think the Queen gets lost here with all of these rooms?” he asked. “Where does she sleep?”

We speculated on how hard it must have been for the knights to walk around in the heavy armor that was on display. And Matt decided it would be fun to play with Queen Mary’s spectacular doll house, in which everything--from penknives to wine bottles to Rolls Royces--was meticulously made one-twelfth life size.

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London is a wonderful city for children--and an especially good choice to introduce them to a foreign culture. Everything--including taxis and television--is decidedly different and for that reason, exciting. There are wonderful museums as well as history at every turn. What child doesn’t revel in castles and tales of kings and knights and princesses? And because English is spoken and Londoners, school children included, seem delighted to talk to American children, kids can gain an understanding of the differences between our country and Britain, trading notes with their English counterparts and even reading signs, without the struggle of grappling with a strange language. In planning our trip we read “Innocents Abroad” by Valerie Wolf Deutsch and Laura Sutherland (Plume Books, $15.95). It’s a well-researched, country-by-country guide that gave us a head start planning a family trip: from where to stay to what to eat to which sites to see. Another good bet for us was “Kidding Around London” by Sarah Lovett (John Muir Publications $8.95). One of the “Kidding Around” series on various cities, it’s a good bet for older kids to read on the flight.

Wherever we went during our week in London shortly before Christmas (the city was beautifully decked out for the holidays), Matt brought a fresh perspective that I hadn’t before considered, despite many visits and a stint in college living there. We saw less (kids can’t take too much sightseeing at once) but we had more fun doing what we did do.

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Even the most unlikely places turned out to be learning experiences. Take Madame Tussaud’s, the best known wax exhibition in the world that goes back more than 200 years. As Matt walked among the famous world leaders and historical figures, he asked for--and got--a brief history lesson. (He couldn’t wait to show his friends his picture next to the Beatles.)

And as was the case in Windsor, Matt struck up conversations with British kids at every turn. He learned as much from these interactions--at the theater; the National Science Museum (a first rate museum that we all enjoyed); in Hamley’s, London’s famous toy store on Regent Street--about the differences, and similarities, of our cultures as he did from all of the sightseeing we did.

There was the school group we met from the London suburbs at the Tower of London, first on any child’s list of to-dos in the city. With its winding tower and turrets and grisly stories of beheadings and skulduggery, it makes for a wonderful afternoon’s outing for all children, no matter where they’re from. The rain and mist seemed to add to the atmosphere. (Give yourselves plenty of time at the Tower. You could easily spend most of a day there investigating the towers, the crown jewels, the exhibits of armor and instruments of torture.)

The Crown Jewels made a lasting impression. “Do they really wear them?” Matt wanted to know. “They seem awfully heavy.”

A noisy school group from Surrey made just as lasting an impression. Matt couldn’t believe they had to wear blazers, ties and--the worst!--short pants to school every day. They couldn’t believe he could go to school dressed in sweat pants and sweat shirt.

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No matter where we were, I tried to let Matt take the lead. I figured if he was interested, he’d learn. We spent hours at the Imperial War Museum which houses tanks and Spitfires and other planes. (Don’t miss The Blitz Experience, where you walk through a reconstruction of an air raid shelter and a bombed 1940 London street.) Matt was very impressed.

We didn’t make it to all of the top tourist attractions. (Cut your itinerary in half if you’re touring with kids.) We left midway through the Changing of the Guard at Buckingham Palace because Matt couldn’t see over the crowd. (It occurs at 11:30 a.m. every other day in winter, daily in summer; get there at least half an hour early for a good viewing spot.) On the other hand, we stumbled onto the Changing of the Horse Guards Parade at Whitehall (held daily at 11 a.m.) and had a great time. There was as much pomp and circumstance, and far fewer people. An added bonus as far as Matt was concerned: the horses. He shot almost a roll of film.

Speaking of pictures, Matt carried his own small inexpensive camera and took his own pictures. I could tell his interest level, in fact, by the numbers of shots he took (none at Westminster Abbey, lots of the pigeons in Kensington Gardens). He kept a journal of the trip, writing a paragraph each night about what we’d done that day.

His favorite memory? Chasing--and catching--a pigeon in Kensington Gardens on a rainy Saturday morning.

Forget force-feeding culture. Just being there is enough.