Japan has unveiled the Grand Ring, a colossal wooden structure spanning 61 square kilometers, as the centerpiece of Expo 2025 Osaka. Designed by renowned architect Sou Fujimoto, this titanesque circular building has been certified by Guinness World Records as the largest wooden structure in the world, embodying traditional Japanese construction methods while showcasing contemporary architectural ambitions.
Every five years, a different city hosts the World Expo, with each event leaving behind architectural legacies that define urban landscapes. The 1900 Paris Exposition is often cited as one of the most influential in architectural history, bequeathing the Grand Palais, Palais de Tokyo, and an indelible Art Deco heritage to the French capital. Following Dubai's 2021 Expo, which was delayed by a year due to the 2020 health crisis, Osaka was selected to host this highly cultural international event in 2025.
The Grand Ring has been erected on the artificial island of Yumeshima in Osaka Bay, at the center of the Japanese archipelago. This circular edifice, constructed entirely from 70% Japanese wood including pine, cedar, and cypress, was built using the traditional Nuki assembly method—a type of joinery employed in local temples and shrines. The structure's circular design was specifically chosen to provide optimal circulation for visitors among the 150 pavilions presented, while offering protection from wind, rain, and sun.
According to Expo 2025 organizers, the building symbolically "embodies the concept of 'Unity in Diversity.'" Architect Sou Fujimoto, who also created L'Arbre Blanc, an impressive hedgehog-like skyscraper in Montpellier, explained to Dezeen: "The exhibitions bring all the wonder of each different country and then stay there for six months. And this format, I think, is very precious, especially in this period of global crisis."
The architectural achievement breaks multiple records with its impressive dimensions. Covering 61,035.55 square meters of surface area with a diameter of 675 meters, the Grand Ring stands 20 meters high. Visitors can freely explore the upper level—its rooftop terrace—which offers breathtaking views over Osaka Bay. The structure demonstrates both ancestral craftsmanship in its construction and decidedly contemporary proportions in its scale.
The traditional Nuki technique used in the assembly represents a remarkable fusion of ancient Japanese woodworking traditions with modern engineering capabilities. This construction method, historically reserved for sacred buildings, has been scaled up to create what may be the most ambitious wooden structure ever attempted. The choice to use predominantly Japanese timber not only supports local forestry but also reinforces the cultural significance of the project.
Like all World Expo infrastructures, the Grand Ring was designed to be dismantleable after the 2025 edition concludes on October 13. However, its future remains undecided. There is hope that, like the Eiffel Tower built for the 1889 Expo, this impressive building will survive the event to become a permanent fixture in Osaka's landscape—a realistic possibility given the exhibition's success, which had already attracted more than 5 million visitors between March and May and aims to welcome 28 million total.
World Expos have served as opportunities for nations and major architectural studios to demonstrate their expertise since the first event in London in 1851. The Eiffel Tower in Paris (1889), the Palau Nacional in Barcelona (1929), and Nashville's Sunsphere (1982) represent just a few of the iconic structures that have become permanent fixtures in their host cities. However, many more remarkable buildings have marked each event without being preserved afterward, such as London's Crystal Palace—a nearly 600-meter-long glass masterpiece built for the 1889 edition but destroyed by fire in 1936.
This year's Expo showcases exceptional pavilion designs from renowned architects worldwide. Kengo Kuma created a pavilion inspired by desert landscapes for Qatar, while Foster + Partners designed Saudi Arabia's pavilion with an ecological approach. Shigeru Ban unveiled a poetic white dome for Japan, and Trahan Architects conceived an immense screen-based structure for the United States. For France, Coldefy and Carlo Ratti Associati created a "Theatre of Life," featuring a sensory experience centered around an interior garden.
Looking ahead, Riyadh, the capital of Saudi Arabia, will host the next World Expo in 2030. France has not served as host since 1937, an edition that left behind the Palais de Tokyo and Palais de Chaillot as Art Deco masterpieces. France had initially presented its candidacy for 2025 but withdrew to focus entirely on the 2024 Paris Olympics. The success of Expo 2025 Osaka, particularly the Grand Ring's innovative approach to sustainable architecture using traditional techniques, may influence future expo designs and demonstrate new possibilities for large-scale wooden construction in contemporary architecture.
