Because Buenos Aires  languished as a backwater of Spain’s empire until the creation of the Viceroyalty of the River Plate in the late 18th century, little remains of its precarious early architecture. The northwestern provinces, though, retain significant colonial monuments in their capital cities and in the countryside. Many are ecclesiastical constructions, ranging from modest chapels in the Quebrada de Humahuaca to full-fledged cathedrals in Córdoba .
For most of the 19th century, porteño architecture evolved from Spanish colonial origins to an Italianate style but, from the early 20th century, the reigning architectural fashion was a beaux arts academicism, both for public buildings and landowning oligarchy’s ornate palacetes (mansions). Many French professionals, including landscape architect Charles Thays, worked on projects in Buenos Aires  and provincial cities.
From the 1930s, the capital developed greater residential and commercial density with buildings such as Retiro ’s Edificio Kavanagh, a 30-story art deco high-rise that was the country’s first air-conditioned structure in the country. The late 20th century saw some hideous developments, such as Clorindo Testa’s brutalist Biblioteca Nacional (National Library) in Palermo . One positive development is the recycling of historical structures, such as the Galerías Pacífico , into contemporary shopping centers, and the brick warehouses at Puerto Madero  into fashionable restaurants and residential lofts.
Architect Alejandro Bustillo created a magnificent northern Patagonian style with Bariloche ’s landmark Centro Cívico. His imitators, though, have failed to achieve the same harmony of nature and culture.
It would be misleading to ignore vernacular architecture styles, ranging from Andean adobes to the distinctive casa chorizo, a long narrow construction on a deep lot. La Boca ’s wood-frame metal-clad houses owe their bright primary colors to the fact that early residents scavenged their paint from ships on the Riachuelo. Houses in the Río Paraná Delta  sit atop stilts to avoid flooding.