Camouflage Architecture: underground buildings

If you're familiar with the Wombles, then you probably encountered underground architecture at any early age.
The Wombles' home was located in the London suburb of Wimbledon, close to the underground station, and embodied every child's dream: subterranean and cave-like, it was made from stuff that society had thrown away. It was an early example of sustainability and the use of recycled building materials.
It's unlikely that the following projects were inspired by the Wombles, but that doesn't mean they're any less successful in terms of their functionality and singularity.

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  Villa Vals, architecture: SeARCH / Bjarne Mastenbroek i.c.w. CMA, photographer: Iwan Baan
• In the Swiss town of Vals, known for its thermal baths, it's not a meteor strike that's created a inverted-dome-shaped hole in the ground: it's a holiday home.
  Astonished by the relaxed planning regulations in the vicinity of the baths – an architectural masterpiece by Peter Zumthor – the owner of the house decided on a minimal approach, so as not to obstruct views of the spa complex.
  
  The building embeds itself fully into the landscape, yet offers sufficient natural light and views out onto the picturesque countryside.
  
  

  Villa Vals, architecture: SeARCH / Bjarne Mastenbroek i.c.w. CMA, photographer: Iwan Baan