There is a painting by Francisco Masriera y Manovens entitled The Belles of the Ball. Painted in 1898, it depicts two sisters posing after a party. The younger, dressed in white, leans forward from a scarlet background, a coquettish look on her face as she urges the artist to hurry up — she has places to go and people to see. Her older sibling stands behind, aloof and uncomfortable, knowing that our eyes are for her sister alone. Once upon a time, she could have been Madrid, and her fun-loving little sister Barcelona — but not any more.

For years, the Spanish capital has taken second billing, a Castilian Hague to the Catalan Amsterdam, but Madrid has now stolen the limelight, sashaying onto the scene with a seductive confidence and the unspoken promise of pleasures more exotic, more sophisticated, than her little sister could ever offer. Drive into Madrid from any dir- ection and you’ll see the cranes in Spain arising from the plain, evidence that the capital is enjoying a period of sustained growth, with new hotels, restaurants, bars, shops and galleries opening weekly in what is indisputably southern Eur-ope’s most exciting city.

VIVA LA DIFERENCIA

I’m standing in a white acrylic corridor in Madrid’s newest hotel. Plasma-blue light pools beneath bulbous walls, making them shrink and swell like an asylum seen through the eyes of an inmate. The room number is slashed onto the flat door with the manic strokes of a madman’s brush, and inside the floor is black and the walls are mirrored.

A rectangular window frames the room, its curtain an electric screen lit by a projection TV. The bed is a red circle in a black ring, the bathroom an open-plan installation cast entirely in blood-red acrylic. If the corridor suggested a futuristic sanatorium, then the room is the sanctuary of a madman’s mind. The lunatic in question is the architect Ron Arad, and if you think his idea of a hotel room is insane, you should see what Zaha Hadid has done six floors below.

Imagine the Star Wars town of Tatooine carved from snow. Envisage a totally white room with no straight edges, where the fixtures take Gaudi’s organic modernism to its illogical conclusion, where you can lie in a bath like a pool hewn from salt so white that, within moments, you lose all per- spective, all sense of depth, all spatial perception. “Perfecto por Kate Moss,” suggests staff member Gorka Urquijo as I walk into a wall.

This is a story of inspiration and of daring, an attempt to meet the future head on with an act of absurd patronage. The idea: to create a hotel that is itself a museum of modern design by giving 17 of the world’s leading architects and designers an open chequebook and one floor or public area each. Do what you like, said the normally staid hotel chain Silken, commissioning the Hotel Puerta America and happily putting the mad into Madrid.

Fifteen minutes from the Puerta del Sol, it stands in a dull residential area beside a motorway, rising 13 floors from the urban wasteland like a luscious purple heliconia, its drab surroundings enhancing its exoticism.

Although not quite finished — the rooftop pool has yet to be installed, and Norman Foster is dallying with rooms built in cream and chocolate leather — this five-star folly opened last week, and we got an exclusive preview.

Rooms are on the small side, with uninspiring views, but that’s not a problem. You haven’t come to look outside, and if you want an executive double with a trouser press and cable porn, there are 100 hotels in Madrid happy to oblige. But if you’ve ever dreamt of falling asleep in a designer store and waking up on a film set, you’ll love the Puerta America.

Up on the 10th, Arata Isozaki has placed a red leather fridge on a black tiled floor. A shoji-style screen throws chequerboard shadows on the black lacquered furniture in a futur- istic evocation of the pleasures of the night. Blade Runner shag pad, I scrawl in my notebook, and it’s hard to avoid the sci-fi analogies. Even the breakfast, with its test tube-like shots of nutrition, seems to suggest you’ve overslept by 30 years.

Hotel Puerta America, Avenida de America 41; 00 34-91 744 5400, www.hotelpuertamerica.com; doubles from £110

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