Austria is a steam-cleaned dream of a country. For every leg-aching mountain pass and ski run, there is a glorious spa - Roman, arty, framed by the Alps, you name it. And we're talking veritable water worlds, where just testing out all the saunas (naked, natürlich) takes an entire afternoon. Here are my five favourites:
1. Alps meets space-age: Aqua Dome, Tyrol
There's something surreal about floating in an outdoor pool surrounded by the snow-capped Ötztal Alps. Especially when that pool resembles a gigantic flying saucer. Make that three flying saucers - one bubbly, one briny, one massaging the wobbly bits. By night, the crystalline Aqua Dome glows amid a halo of steam. If that sounds impressive, wait until you see the 'textile-free' sauna village. This steamy wonderland includes a loft sauna, a canyon sauna with the occasional thunderstorm, a numbingly cold ice grotto and (my personal favourite) a chamber-like shower where you can choose between mist, tropical rain and a fully blown waterfall - quite a Niagara as it happens, so stand back.
2. Roman bath: Römertherme, Wienerwald
Surrounded by vineyards, Baden in the Vienna Woods was a beloved retreat of the good-living Romans, a place where they came to wallow in the healing waters and drink deep of its wine - as did Beethoven and the holidaying Hapsburgs, incidentally. Agreed, the sulphuric hot springs smell off-puttingly rotten-eggy, but stick with it in the jetted tubs of the Römertherme or the Thermalstrandbad outdoor pool for fabulously smooth skin and a glowing complexion. Come in autumn and you can combine spa time with new wine in the rustic Heurigen (wine taverns) and vinotherapy treatments.
3. Where art meets water: Rogner Bad Blumau, Styria
The eco-savvy Rogner Bad Blumau bears the curvy imprint of that most eccentric of Austrian architects: Friedensreich Hundertwasser. The dream-like waterscape is a cross between Babylon, with its columns, domes and rooftop gardens, and Teletubby land, with its undulating meadows and rainbow colours. Alongside the usual steam and sauna fun, there's a dead sea salt grotto and two curative hot springs - the mild Melchior and the hardcore Vulkania, whose mineral-rich waters leave skin silky soft. For full-on pampering, there are treatments from sound meditation to invigorating Styrian elderberry wraps.
4. Radon therapy: Bad Gastein, Salzburgerland
'Only sick bones I thought of bringing, where mystically your hot water springs,' wrote Empress Elisabeth (Sissi) of the healing waters in Bad Gastein, a cliff-hanger of a town in the Hohe Tauern mountains. The resort had its belle-époque heyday in the 19th century, but its radon-laced waters - said to cure a hypochondriac's handbook of ills - are just as therapeutic today. Take them in the grotto-like pools of the Felsentherme and the architecturally innovative Alpen Therme. Or, for greater impact, venture deep into the bowels of the Gasteiner Heilstollen, a medieval gold mine turned health centre, to absorb the radon (€28 for a taster session).
5. That Caribbean feeling: Therme Geinberg
A Caribbean-style lagoon is the last thing you expect to see in the heart of Upper Austria's rural Innviertel. But who cares if Therme Geinberg is incongruous - bring on the daiquiris, the starlit saunas smelling divinely of coconuts, the soporific cabana-bed massages, the sand crunching underfoot... Close your eyes and you could be in Antigua. Well, almost. If the weather packs up, as it often does, you can bathe in thermal, salt- and fresh-water pools, or get the energy flowing with a stimulating Tui-Na massage.
Lonely Planet author Kerry Christiani is researching the Austria guidebook in Tyrol.