In many modern cities the cross-shaped structure is still evident, inheritance of the castrum, the Roman camp that stood out for its orthogonal plan and the roads perpendicular to each other called Cardo and Decumanus. This is the structure that inspired the design of the Expo Milano 2015 Exposition Site. The Decumanus crosses the entire site from east to west for 1,5 kilometers, and it intersects with the Cardo, 350 metres long, which connects the north and south of the Exhibition Site and includes the exhibition proposal of the host country, Italy. Maffeis Engineering designed the structure and membrane systems of both these “roads”.