As preparations for the 2025 World Expo in Osaka are in full swing, the iconic giant wooden roof known as the “Grand Ring” was on display in its entire circular shape at the venue on Wednesday.

According to the Expo organizers, the ring will be one of the largest wooden structures in the world. It will have a circumference of about two kilometers and a maximum height of about 20 meters. Construction work is expected to last until February next year.

The area under the roof serves as the main promenade for the Expo site, providing shelter from rain and sunlight during the event, which runs from April 13 to October 13 next year. From the roof of the ring, one can see the surrounding pavilions of the international participants.

A photo taken from a helicopter by Kyodo News shows the giant wooden roof, known as the “Grand Ring,” in its full circular shape at the World Expo 2025 venue on Yumeshima, an artificial island in Osaka, on Aug. 21, 2024. (Kyodo)

After assembling the lumber for the wooden structure, a pedestrian ramp on the roof was completed on Wednesday.

The remaining work includes the installation of elevators and the creation of green spaces.

With rising material and labor costs, the ring, which is expected to cost around 35 billion yen ($240 million) to build, has faced criticism that it is a waste of public money, with opposition lawmakers even calling it the “world’s most expensive parasol.”

The Expo organizer is considering recycling parts of the ring structure after it is dismantled following the World Expo.

Japan will host the World Expo in 2025 for the third time in the event’s 170-year history. The international exhibition is expected to attract more than 20 million visitors from around the world to Yumeshima, an artificial island in Osaka Bay.