The imposing peaks and impeccable gardens of France's great châteaux are among the glories of its architectural heritage. Some are literal castles, fortified with battlements and stout walls to repel attacks, but most were built as manor houses for aristocratic families, the equivalent of the English country house. Châteaux are found all over France, with architectural styles depending as much on the budget and imagination of the original owners as on the period of their construction. But by far the greatest concentration is in the Loire Valley, where some 300 of these grand residences now form stages on a hugely popular tourist trail.