The Swiss Development Group has started work on a residential, hospitality and spa project in Leukerbad, in the heart of the Swiss Alps, where the Valais mountain's thermal waters have bubbled at a temperature of 51C since Roman times.

Situated 1,402m above sea level, the site, designed by US architects Michael Graves & Associates, is set to host 28 luxury apartments boasting their own natural thermal whirlpools and outdoor 'moon bath' pools. It will also include a five-star resort hotel, operated by Kempinski.

Meanwhile, US spa consultancy Under a Tree will be developing Spa 51*, a contemporary luxury interpretation of Russian and Alpine spa traditions.

The 15,000sq ft (1,400sq m) spa is set to feature a fitness centre and outdoor lap pool, plus around 10 treatment rooms which will connect to a European-style bathhouse with substantial hydrothermal experiences.

Bathhouse facilities will comprise a traditional Russian sauna - a high heat chamber that can reach temperatures of 100C - a cooler tepidarium, an inhalation room, steam room, plunge pool and resting area which lead to an indoor mineral pool joined by swim-through passage to an al-fresco hydromassage pool and relaxation gardens with views over the picturesque valley.

There will also be a separate expansive Banya Suite available for private bookings which will have its own Russian sauna, tepidarium, plunge pool and deluge shower, plus a lounge, dining facilities and treatment room and outdoor space with nautrally-heated soaking barrels and another cold plunge.

In a contemporary, recreational twist, the Banya Suite will be accessible to the onsite night club via secret 'speakeasy' entrance, providing revellers with the opportunity to create their own celebrations in a unique context.

Spa treatments and personal care services are rooted in the theme of lifestyle wellness, leveraging the therapeutic effects of mineral water and contrast thermal bathing to promote relaxation, aid detoxification and to help with sports conditioning and stress management.