Clouds gather over Japan's ambitious Osaka World Expo

This April 2, 2024, photo shows construction of the 'Grand Roof,' one of the world's largest wooden structures, at the site of the 2025 Expo on Yumeshima island, an area of reclaimed land in Osaka, Japan. FILE - This Oct. 12, 2023, photo shows the 'Tower of the Sun' by Japanese artist Taro Okamoto. It was the symbol of the 1970 Osaka Expo and now the location of the Expo Commemoration Park in Suita, Osaka prefecture.

One of the largest wooden structures ever built is taking shape in Osaka but hopes that Expo 2025 will unite the world are being dogged by cost blowouts and a lack of public enthusiasm.