Catalan Vault

The Catalan vaulting technique in particular made it possible to build spectacular structures, with designs by, for example, Antoni Gaudí or Rafael Guastavino, and was employed in a wide range of applications during the first half of the twentieth century, at which time it was replaced by new methods of construction and modern building materials such as concrete and steel.
http://detail-online.com/inspiration/technology-the-catalan-vault-%E2%80%93-a-historical-%C2%ADstructural-principle-with-a-bright-future-106565.html

old and new

Awarded the 2005 Architectural Review Award for Emerging Architecture, the house was built off-site and inserted into the fragile existing structure. The result is a modern new wood interior with a charming, albeit crumbling, exterior. the architects able to extend the life of an old building through simple yet clever mean. FNP Architekten

simple yet clever mean. FNP Architekten.

Mosque of Cordoba

The expansive prayer hall seems magnified by its repeated geometry. It is built with recycled ancient Roman columns from which sprout a striking combination of two-tiered, symmetrical arches, formed of stone and red brick. 

UGALDE HOUSE

UGALDE HOUSE, Jose Antonio Coderch, Caldes d'Estrac, Barcelona, 1951.

The house is excellently situated, set right into the plot to the extent that it fuses with it. The original sketches, which reveal a preoccupation with the preservation of certain views and of the existing vegetation, were in due course followed up by painstaking formal research. (www.casaugalde.com)