Initial plan

The initial plan had the following elements:

• 50 per cent of the area occupied by pavilions, 35 per cent dedicated to space around each pavilion and the remaining 15 per cent a green perimeter around the site
• Piazza Italia and Piazza Expo at either end of the main boulevard, the former dominated by the 7,000-square-metre (1.7-acre) Italy pavilion and flanked by a second square (Piazza delle Regioni)
• A large, artificial lake surrounded by the 20 pavilions representing the Italian regions
• A 12,000-seat amphitheatre covering 9,000 m² (2.2 acres) and a 6,000-seat, 6,000-square-metre (1.5-acre) auditorium
• Country pavilions in three sizes, depending on the financial resources of the participating country
• Three pavilions dedicated to geographic areas: Asia, Africa and Latin America and the Caribbean

A 100-hectare (250-acre) service area was planned near the main Expo site with hotels, parking facilities, stores, a convention centre, green areas, a business centre available to Expo participants and a 12-hectare (30-acre) Expo Village to house staff, volunteers and security and administrative personnel.

The following thematic pavilions were also planned:

• What the World Eats: At the base of the Expo tower and in the pedestrian bridge connecting the Rho-Pero fairgrounds to the expo site
• Science and Conscience
• Tales of Land, Air and Water
• The Food Spiral
• The Right to Eat Well
• In the Realm of the Senses, in Piazza Italia
• Equilibrium
• The Art of Food

Concept

Expo 2015's concept was presented on September 8, 2009. It was designed by a committee of four architects: Stefano Boeri, Richard Burdett, Mark Rylander and Jacques Herzog.

The main idea was to trace two avenues (a main and a secondary avenue), representing the ancient Roman layout of a cardo and a decumanus. The initial idea of a "classical" site composed of avenues and pavilions was replaced by the idea of a "light" Expo composed of exhibition areas arranged across the main boulevard. The exhibition areas, identical for each country, recreated the typical food cycle of each nation from production to consumption. The centre of the avenue was occupied by a table in front of the country pavilions extending the length of the site, where visitors could sample foods produced in each country's pavilion. The area would be covered by large, tent-like structures to convey the idea of a global marketplace.

A second idea was to build large greenhouses on the site to reproduce the earth's principal biomes. These would be thematic pavilions for the cultivation and production of basic foodstuffs used in the individual country pavilions. Each country would have a dedicated greenhouse in its exhibition area. In this version of the site, water remained an important element but was shifted toward the exterior as a large, navigable canal surrounding the site. A large lake was also included in the design. Additional elements included a large, excavated amphitheatre and a hill, one at each end of the boulevard; expo village facilities across the encircling canal from the site, and redevelopment of the post-office building as a centre for sustainable development.

Master plan

The master plan for Expo 2015, coordinated by Stefano Boeri, was delivered to the BIE during its April 30, 2010 registration ceremony in Paris. Changes included:

• Each exhibiting country could rent areas ranging from 400 to 6,000 m² (4,300 to 64,600 sq ft).
• Buildable areas were reduced to 30 per cent of the area assigned to each exhibitor.
• The large, but not navigable, canal around the area is maintained;
• The tent roofing remained only along the axes of the cardo and the decumanus.
• Greenhouses would be in a 50,000 m² (12-acre) zone.
• The circular canal became a theatre on the water, with a central stage.
• The green hill opposite the amphitheatre would be built of earth from the amphitheatre excavation.
• An auditorium was included.

Countries

Each participating country was hosted in a self-constructed pavilion and included on the Expo website.^[10] Some countries, such as Belarus,^[11] Belgium,^[12] Israel^[13] and Germany,^[14] created external websites. As part of a reciprocity protocol with Expo 2010 in Shanghai, on December 8, 2008, China was the first country to formalise its participation in Expo 2015. The first country outside the reciprocity protocol to confirm its participation was Switzerland, on February 3, 2011.^[15] As in other years, during the Expo visitors could purchase a passport which could be stamped.

Two major countries which did not participate were Australia and Canada, who withdrew despite participating in the previous Expo in Shanghai, citing budgetary restrictions.^[16]

The following countries participated:^[17]