Belgium - Major Town Houses of the Architect Victor Horta (Brussels)

"The four major town houses - Hôtel Tassel, Hôtel Solvay, Hôtel van Eetvelde, and Maison & Atelier Horta - located in Brussels and designed by the architect Victor Horta, one of the earliest initiators of Art Nouveau, are some of the most remarkable pioneering works of architecture of the end of the 19th century. The stylistic revolution represented by these works is characterised by their open plan, the diffusion of light, and the brilliant joining of the curved lines of decoration with the structure of the building." 
Source: UNESCO World Heritage