Some pavilions were just plain inexplicable. Why did Malaysia's offering - supposed to represent four seeds - look like oversized eggs that had toppled on their sides? And did Belarus really think a giant wheel-cum-digital-billboard cutting through a grassy hill was the best way to showcase the importance of conservation?

Adherence to the expo's stated theme - sustainable agriculture or "Feeding the Planet" - was often shaky and many of the structures appeared so permanent - and huge - it was difficult to imagine how they could possibly be re-used or dismantled at the end of the expo with any meaningful degree of environmental consciousness.

The British pavilion was a notable exception and shone for its use of modular staging and an entirely reusable bolted-steel framework. Representing a bee's journey through a meadow via an orchard on its way to a beehive, it was manufactured by Stage One, a fabrication and engineering company based in Britain that specialises in producing short-term but memorable installations and events, such as the Olympics. The intricate 14-metre-high latticed sculpture at this pavilion's heart used sound and light to simulate the activity of a beehive and is set to find a new home in Britain as an artwork when the fair is over.

"The expo is very much a political and commercial event," says Yichen Lu, who designed the China pavilion in collaboration with Tsinghua University in Beijing, in answer to concerns about national idiosyncrasy and ego being favoured by countries in their pavilion designs. "You cannot expect too much."

Yet Lu believes it is important for countries, especially more recently developed countries, to participate and have a presence. "This is the first time China has built a national pavilion outside its own country," he continues. "It's only been about 40 years since China opened up to the world and the end of the Cultural Revolution. That's not very long."

The Chinese pavilion's large-span undulating roof represents the merging of the Beijing skyline on the north side and the contour of the Guilin mountain range on the south. "It's an expression of hope that city and nature can exist in harmony," explains Lu, who founded his architectural practice, Studio Link-Arc, in New York in 2011 while continuing to teach at Tsinghua University.

The China pavilion's humble, open and uplifting architecture and generous use of natural materials, such as bamboo for the roof panels and glulam (glued laminated timbers) for the structure, speaks of a "new China" that "needs to be truthful and welcoming", he continues. Its form and internal circulation say something important about his generation's intentions and values, he says.

"The main entrance for the building is humble and has a low roof but you leave from a monumental very high space. The most important internal spaces are given over to the visitors, to the public, not to VIPs."

But China's contribution to the expo does not end there. On the northern end of the site, next to a large lake, is the contribution by China's largest real-estate company, Vanke. Designed by New York-based Studio Libeskind, the curvilinear pavilion (the first ever by a Chinese company at an expo) had originally been conceived as an agricultural landscape but has been rebranded a dragon since its reptilian form and scaly skin have fully emerged.

Though relatively small, it makes the most of its standalone site with a red faceted skin of metallic ceramic tiles made by innovative Italian tile manufacturer Casalgrande Padana. Their textured surface and unique supporting structure means each tile looks as if it is floating and the building's colour constantly mutates from a glowering dark red to a bright gold and even a brilliant white, depending on the time of day and angle of sight.

Like much of what there is to see at the expo it is not subtle, but it provides moments of awe and wonder, as well as insight into how people, countries and corporations would like to be viewed by the rest of the world.