Among his works are El Silencio Redevelopment which included 7797 apartments and 207 shop premises and the Ciudad Universitaria, the main campus of the Central University of Venezuela.

In 1922, following the footsteps of his brother Marcel, Carlos Raúl was admitted to the Second Class of the Department of Architecture of the École des Beaux-Arts and entered the workshop of Gabriel Héraud.

During that time he collaborated on a project for a Hôtel d'ambassade a construire dans un pays d'Extreme Orient with another student of Héraud's workshop, Roger-Leopold Hummel, which won the Second prize of the Grand Prix de Rome in 1928.

After gaining some experience in France and the United States, Villanueva arrives in Venezuela full of enthusiasm and ideas; in particular, thanks to the influence of his close friend Auguste Perret.

Built on the site of the old Hacienda Ibarra - which originally belonged to Simon Bolívar's family - and connected to the new city center around Plaza Venezuela, the project meant a massive undertaking of both urban planning and architectural design.

This vast urban complex of about 2 square kilometres includes a total of 40 buildings and it remains one of the most successful applications of Modern Architecture in Latin America.

Villanueva worked closely with all the artists who contributed with their oeuvres and personally supervised the project for over 25 years until the late 60's when his deteriorating health forced him to leave some buildings in the design stage.