Art Nouveau (French for "new art") is a style in art, architecture and design that peaked in popularity at the beginning of the 20th century.
Other, more localized terms for the cluster of self-consciously radical, somewhat mannered reformist chic that formed a prelude to 20th-century modernism, included "Jugendstil" in Germany and the Netherlands, named for the snappy avant-garde periodical Jugend ('Youth'), Młoda Polska (Young Poland) in Poland, or "Sezessionsstil" ('Secessionism') in Vienna, where forward-looking artists and designers seceded from the mainstream salon exhibitions, to exhibit on their own in more congenial surroundings.

In Russia, the movement revolved around the art magazine World of Art, which spawned the revolutionary Ballets Russes.
In Italy, "Stile Liberty" was named for the London shop, Liberty & Co, which distributed modern design emanating from the Arts and Crafts movement, a sign both of the Art Nouveau's commercial aspect and the "imported" character that it always retained in Italy.
In Catalonia, the movement was centred in Barcelona and was known as "modernisme", with Antoni Gaudí as the most noteworthy practitioner.
Art Nouveau was also a force in Eastern Europe, with the influence of Alfons Mucha in Moravia (part of the modern Czech Republic) and Latvian Romanticism (Riga, the capital of Latvia, is home to over 800 Art Nouveau buildings).

The term art nouveau was coined in Belgium in 1884 by a group of artists known as Les XX, who described themselves as being "votaries of art nouveau."
Eleven years later, Siegfried Bing, a German-born dealer, opened a shop in Paris that he called L'Art Nouveau, and its success brought the term into widespread use.

Pomposity of intent and orthodoxy of style - these were the main traits of European architecture against which Art Nouveau rose up towards the end of the last century.
It was a time of rapid urban growth, when the rich wanted to show off their newly-acquired wealth in town houses and other architectural statements that took themselves so seriously that they seemed heartless.
Art Nouveau, in contrast, was a vision that sprang straight from the heart as a rejection of the grey uniformization of the environment: of dwellings, furniture, tableware and other artefacts that strongly shape the ways in which people live and feel about their daily lives.
Art Nouveau expressed nostalgia for Nature and the past, for the non-urban and the non-modern, for the anti-rational swirls of vines and flower stems, the rough texture of pine cones, and more generally for pre-industrial asymmetry.
It also grew in tune with the medieval longings that so marked the aesthetics of the late nineteenth century, and were often connected with movements of national revival.
But Art Nouveau also looked aged, happily seizing the materials of its day and proving itself to be a force for ingenious innovation.
Did stone attest to the solidity and incomes of the wealthy, whose pomposity Art Nouveau mocked? The new style flaunted its creativity by making this staid material come alive with turbulent vegetation, mythical beasts and human beings with expressions so pure they seem to pre-date the very notion of sin. Art Nouveau worked stone as though it were clay, and also embraced new media such as polychrome glazing, wrought iron, exposed steel, and glass (stained or futuristically sworled), often in astonishing and unprecedented combinations in the same work, be it a house or a piece of furniture.
In terms of inspiration and impact, the Art Nouveau vision also looked outwards.
Mogul influence can also be seen (in certain towers, for instance), and some Art Nouveau exponents in Central Europe drew on references from further to the east.
 

Magnificent collection of Art Nouveau objects.