Neuschwanstein Castle near the Bavarian village of Schwangau is the German National Tourist Office's favorite promotional image. Floating above enchanted mists, its spires rank among the most famous in the world. Written beneath it on one of the many posters, a caption reads, "King Ludwig's dearest wish was to make all his subjects happy. So he built them fairy-tale castles."

Not true. History in fact records that the dearest wish of "mad" King Ludwig II was that after his death, his fairy-tale castles be blown up. That rather than loving his subjects, he despised them. He particularly loathed the way they "bowed and scraped" before him and couldn't stomach the thought of his magnificent buildings sullied by their admiration after he died. The mere contact with their eyes, he said, would "soil and desecrate them."

It is ironic perhaps that such facts make a visit all the more appealing. Not so much for the haunting beauty of Neuschwanstein's white towers; or because today it is among Germany's most visited attractions (2 million tourists a year) and pride of the German National Tourist Board; or that Walt Disney copied parts of it for one of his theme- park castles. But rather because unlike most mad kings, Ludwig left the world a vivid 3-D conducted tour of how his imagination worked.

To sample this view into Ludwig's mind, however, a short drive east from the famed Neuschwanstein is required. Down past the dramatically lit twin castle at Hohenschwangau, then 25 miles along the northern foothills of the Alps, you will find his third, far-lesser-known creation at Linderhof--which he described as his "modest palace."

In fact its "modesty" turns out as an elaborate French-Baroque chateau, set in a large landscaped garden with water cascades and several uninhibited follies. Having created his fairy-tale castle among the smoking mountains and waterfall at Neuschwanstein, Ludwig here decided to imitate the excesses of Versailles--as befitting any king. Naturally, Linderhof provides the expected ornamental gardens, fountains, neatly trimmed hedges and statues. But standing before a pair of glowingly lifelike gold cherubs, you start to pick up the surreal edges of a monarch who once declared his capital city Munich should be "set alight at all four corners." Also the man who once addressed Richard Wagner, "Holy one! I am like a spark longing to be lit and inflamed in the rays of your sun," and ended up funding the composer's career, declaring that "I shall banish forever the lower concerns of your daily life." Rumor has it this enabled some of the musician's greater operatic works.

Queuing up for Linderhof's English-language tour, watching the German tours come and go, I begin swapping notes on the poet-king with other native speakers--in this case a couple of GIs on leave from their German base, just returned from a walk around the Linderhof estate. "The Grotto, man," they keep saying, "just like Disney. Best ride in Germany!"

Such enthusiasm confirms a suspicion that by today's standards Ludwig might not be mad at all. Indeed such architecture has become a shrewd investment. He allows us tourists to think him crazy, as we delightedly hand over dozens of deutsche marks for the privilege.

The house itself brings on the feeling of walking around the head not of a madman but a full-on romantic. Everything is deliciously a little off. Too many mirrors in the Mirror Room; too much gilding around the Royal Bedroom; and a Wagnerian "Ring" Cycle motif every few yards. It leaves you never quite sure what will happen next--precisely the effect Disney tried to re-create.

Especially so in the Royal Dining Room. As one of the GIs put it succinctly, "Where's the table?" Instead of a long slab of polished oak fit for banquets, a simple four-seater stands in the center. Unlike most kings before or since, Ludwig hated guests, much preferring to eat alone. But true to character he took this a stage further, designing the table to descend through the floor to the kitchen, thus avoiding the demeaning sight of servants (who unsettled his mood) and courtiers (who irritated him to distraction).

At length, one begins to get a feeling of semi-regression into childhood--the king's. The tour guide told stories of Ludwig not wanting to be king and frequently having to be persuaded not to abdicate. He hired set designers, not architects, to draw up plans for his chateaux.

But the Grotto gives the greatest insight of all into his royal out-of-placeness, with its uncompromising devotion to the music and ideals of Richard Wagner. Not satisfied to be merely the composer's principal patron, Ludwig attempted to re-create, in three dimensions, what until then could only be found inside the listener's mind. Thus the Grotto at Linderhof can genuinely be described as one of the world's first theme-park experiences.

Constructed about 325 yards from the main house, this large artificial cave was built solely to give the performance of Wagner's "Lohengrin" a walk-through feel. The Grotto is filled with stalactites hanging around a small lake with a wave machine. The water was heated to 91 degrees to permit real Rhine Maidens to languish in the ripples. On the back wall a mural of frolicking cherubs was lit in the 1860s by one of the world's first 10 electric generators--simply so Ludwig could easily alter the lighting effects. Red allowed him to imagine the mountain cave of Venus in Tannhauser, blue the Grotto of Capri. To the left fake Rhinegold glows across the waves, in his day enhanced by real swans forced to swim (certainly against their wills) across the cave.

But perhaps most extraordinary of all was the open-shell boat now proudly on display, led by a gold Cupid on the prow. This, ironically, ended up as the only thing of use in the Grotto. Like most romantics, Ludwig overlooked a crucial practicality--in this case, acoustics. While providing enough room for a full orchestra and choir, Ludwig left space for only six in the audience--since whose pleasure but the king's mattered? But the sound proved so ghastly no opera was ever performed. Instead its use came at night when Ludwig had himself rowed moodily around the lake among the disgruntled swans.

Stepping outside is like unhooking yourself from a 19th-century virtual-reality machine. You walk out into the estate wondering what is real and what is fantasy. Six hundred feet away, Ludwig's Moorish Kiosk sprouts from the grass. A miniature stone temple, kept permanently locked and containing nothing but one fabulous Oriental throne, surrounded by peacock fans and stained glass.

On any other occasion this might appear out of place. But after three hours inside King Ludwig's head, this, along with the 20th century's plethora of theme extravaganzas, could hardly seem more normal.

Linderhof is open 9 a.m. to 5:30 p.m. April through September; 9:30 a.m.-noon and 1-4 p.m. October through March. English-language tours of Linderhof are offered year-round, though only the palace itself (no park buildings) can be viewed in the winter. Summer tours are about $5.25, less in winter. For information on travel to Germany, contact the German National Tourist Office, 212-661-7200, Peter Nasmyth's book, "Georgia, in the Mountains of Poetry," is published by St. Martin's Press.