• Château d'If (off Marseille, Provence): One of France's most notorious fortresses, this was the famous state prison whose mysterious guest was the Man in the Iron Mask. Alexandre Dumas's Count of Monte Cristo made the legend famous around the world. It doesn't really matter that the story was apocryphal; people flock here because they believe it, just as they go to Verona, Italy, to see where Romeo and Juliet lived. The château was built by François I in 1524 as part of the defenses of Marseille.
  • Palais des Papes (Avignon, Provence): This was the seat of Avignon's brief golden age as the capital of Christendom. From 1352 to 1377, seven popes -- all French -- ruled here, a period dubbed "the Babylonian Captivity." They lived with pomp and circumstance. The Italian poet Petrarch denounced the palace as "the shame of mankind, a sink of vice." Even after Gregory XI was persuaded to return to Rome, some cardinals remained, electing their own pope or "anti-pope," who was finally expelled by force in 1403.
  • Château de la Napoule (Mandelieu, La Napoule, French Riviera): The Riviera's most eccentric château is also the most fascinating. This great medieval castle was purchased in 1919 by American sculptor Henry Clews, heir to a banking fortune. He lived, worked, and was buried here in 1937. In this castle, Clews created his own grotesque menagerie -- scorpions, pelicans, gnomes, monkeys, lizards, whatever came to his tortured mind.
  • Les Grands Appartements du Palais (Monte Carlo, Monaco, French Riviera): The world has known greater palaces, but this Italianate one on "the Rock" houses the man who presides over the tiny but incredibly rich principality of Monaco, Europe's second-smallest state. In 2011, this palace hosted the civil wedding celebrations for Prince Albert II and his bride Charlene Wittstock. When the prince is here, a flag flies. You can watch the changing of the guard every day at 11:55am. The throne room is decorated with paintings by Holbein, Bruegel, and others, and in one wing of the palace is a museum devoted to souvenirs of Napoleon.
  • Villa Kérylos (Beaulieu-sur-Mer, French Riviera): This villa is a faithful reconstruction of an ancient Greek palace, built between 1902 and 1908 by the eccentric archaeologist Théodore Reinach. Designated a historic monument of France, with its white, yellow, and lavender Italian marble and its ivory and bronze copies of vases and mosaics, Kérylos is a visual knockout.
  • Villa Ephrussi de Rothschild (Saint-Jean-Cap-Ferrat, French Riviera): This ornate pink Belle Époque palace and its immaculate gardens evoke the golden era of the Riviera. Baronne Ephrussi de Rothschild left a treasure-trove of art and artifacts to the Institut de France on her death in 1934. The Villa Ephrussi, the 1912 palace that contains these pieces, reveals what a woman with unlimited wealth and highly eclectic tastes can collect. It's all here: paintings by Carpaccio and other masters of the Venetian Renaissance; canvases by Sisley, Renoir, and Monet; Ming vases; Dresden porcelain; and more. An eccentric, she named her house after the ocean liner Ile de France and insisted that her 35 gardeners dress as sailors.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.