Some artists' palaces are worthy of every superlative. Straight out of the boundless imagination of their creators, unique buildings now fascinate visitors to France: Postman Cheval's Ideal Palace in Provence, the estate of Robert Tatin in Mayenne and the "Bubble Palace" (pictured) on the French Riviera. FRANCE 24 takes you on a journey to the confines of fantasy to discover three palaces that share the fact they are unlike any other.