Jeanneret made more sketches of the Parthenon on the Acropolis in Athens than almost any other building. For him, the Greek temple, with its distinct structures and forms, embodied the perfect harmony between function and aesthetics. Its dominant place in the landscape impresses him. He sees the building as a timeless achievement of human civilisation. Jeanneret praised the use of standardised building elements like the Doric columns, which are placed at regular intervals. The Parthenon embodied the principles he aimed for in modern architecture.

In 1911, Jeanneret spent several weeks in Istanbul. He was fascinated by the distinctive skyline and historical buildings like the Hagia Sophia, the Blue Mosque, and Topkapı Palace. For him, the city was a harmonious blend of nature and architecture. Later, he incorporated various influences from Byzantine and Ottoman architecture, especially the clear geometric forms and the sophisticated use of light.

Jeanneret recorded the impressions of his travels from 1907 to 1911 in numerous sketchbooks. Drawing was a way for him to capture, organise, and understand what he saw. He focused on architecture, art, landscapes, cultural history, and everyday life, as well as the experience of travelling itself. Throughout his life, he maintained the habit of keeping a travel diary in the form of drawings.

In his early drawings and watercolours, Jeanneret often engaged with nature. Many works show his interest in spatial structures and phenomena. His studies also focused on landscapes. Meandering streams, views of the horizon or the sea, and natural processes are themes that repeatedly appear in both his architecture and his art.

On his trip to Italy, Jeanneret admired the simple and balanced forms of ancient Roman architecture – domes, pyramids, and squares. In 1923, he expressed this sense of esteem in the book Vers une architecture. However, he also criticised the way too many decorative elements, such as acanthus leaves (ornaments) on Corinthian columns, disfigured these ‘pure volumes.’ He even called the Rome of the Renaissance and Baroque periods an ‘abomination.’ To illustrate his book, he used images from popular travel guides of the time.

A chapter of Vers une architecture reveals Jeanneret’s intensive engagement with Greek architecture years earlier. He used images of the Parthenon on the Acropolis of Athens to illustrate the importance of ‘natural’ proportions. Following these principles makes architecture a pure and timeless ‘creation of the mind’ – and architecture becomes art.