Editor's note: Alexandra Munroe is Samsung senior curator of Asian art at the Guggenheim Museum, New York, and a pioneering authority on Asian art and transnational art studies. She has spearheaded the international museum's petition calling for Ai Weiwei's release.
(CNN) -- The "Circle of Animals/Zodiac Heads" sculpture exhibit features 12 spectacular bronze heads, each 10 feet high, installed in a semicircle at New York's Grand Army Plaza.
Chinese artist Ai Weiwei's "Zodiac Heads" are enlarged versions of those designed in the 18th century by European Jesuits for the Manchu emperor Qianlong as part of his garden palace, the Yuanming Yuan, outside the Qing-era capital, Beijing.
Representing both the 12-year and 24-hour cycles of the Chinese zodiac, the fantastically realist cast bronze animal heads originally adorned the famous fountain clock in the European-style gardens, each spouting water for two hours a day.
The original heads were looted when this vast imperial compound was destroyed by French and British troops during the Second Opium War in 1860, an event that has epitomized China's national humiliation and triggered anti-Westernism ever since.
When the 18th-century heads began to resurface in the international art market in 2000, China was determined to repatriate them at any cost.
When two of the zodiac heads -- rat and rabbit -- came up at the 2009 auction of the collection of the late fashion designer Yves Saint Laurent and his partner Pierre Berge, the Chinese government sued unsuccessfully for their return.
A Chinese national bid $40 million for both heads and then refused to pay for them, citing his sabotage as "patriotic duty."
Coming in the wake of the 2008 Beijing Olympics, the summit of renewed cultural nationalism, China's reclamation frenzy reveals deep insecurity about its own modern history and global identity.
The conceptual power of Ai's reimagination of the "Zodiac Heads" lies in the many layers of meaning and irony embedded in this international controversy.
Ai mines these fissures, exaggerating the hybrid origin of the works -- European, Manchurian and Chinese -- inventing imagery for the still-missing animals, and casting them in multiples to be exhibited simultaneously in New York and London.
"My work is always dealing with real or fake, authenticity and value and how value relates to current political and social understandings and misunderstandings," Ai said in a statement earlier this year. "However, because 'Circle of Animals/Zodiac Heads' is composed of animal heads, it's a work that everyone can understand, including children and people who are not in the art world. I think it's more important to show your work to the public. That's what I really care about."
Ai was not present at the opening ceremonies for the New York and London exhibits. He has been detained since April 3 by the Chinese government, which is investigating him for alleged "economic crimes."
"We stand in solidarity with the billions of people who do not have the most fundamental of all human rights, the most cherished of all American values, and the most valuable of all New York City's riches: free expression," New York Mayor Michael Bloomberg said at the opening ceremony on May 5.
His words echoed an earlier statement by Ai: "Without freedom of expression, there is no modern world, just a barbaric one."
Ai's prolific and popular Internet rants were censored and removed from cyberspace in May 2009, but his online writings persist in book form, unnerving hardliners in Beijing.
One typical post reads: "Only rule of law can make the game equal, and only when it is equal can people's participation possibly be extraordinary."
The son of a patriotic poet who was exiled, then rehabilitated, Ai, 53, is one of the most famous members of the generation that was raised in Mao's Communist China, witnessed the party-state's failure and benefited most from its reforms. His generation has been at the forefront of China's economic miracle, propelling its super-power status and astounding transformation.
As a founder of China's first avant-garde group, The Stars, in 1979, and a conceptual artist on the fringe of New York's downtown art scene during the 1980s, Ai said early on, "This so-called contemporary art is not a form but a philosophy of society."
Everything about Ai's multidisciplinary art is social.
He stages his work through a strangely furtive and compassionate network of relationships, collaborations and collectives across all arenas of his creative terrain: as a sculptor working with traditional carpenters to create objects made from recycled Chinese furniture; as an architect designing his studio compound in Beijing; and as an installation artist commissioning 100 million "Sunflower Seeds" from porcelain factories in Qindechen for deposit at the Tate's vast Turbine Hall in London.
From 2006, Ai increasingly turned to the Internet as a form of "social sculpture." Outraged at the repression of popular protests in the aftermath of the Sichuan earthquake of April 2008, Ai galvanized local communities to research the names of the thousands of children whose deaths were blamed on shoddy school-building construction.
Working with 30 volunteers in opposition to the government, which denied the deaths and threatened parents with reprisals if they cooperated, Ai published more than 4,000 names on his blog.
At a solo show in Munich's Haus der Kunst, he covered the entire museum façade with 9,000 backpacks like those found in the rubble and arranged them by color to spell out one mother's remembrance of her child: "She lived happily for seven years in this world."
Ai shot to international prominence as co-designer -- with the Swiss architects Herzog and de Meuron -- of Beijing's National Stadium, known as the "Bird's Nest," the main site of the 2008 Olympics.
But rather than enjoy the perks of national stardom as China geared up for its arrival on the global stage, Ai used his position to lambaste the government's social injustices and repression of free expression through a relentless series of "digital rants."
In the process, he also became the latest in a long line of modern Chinese artists and thinkers whose exasperation occasionally assumes the form of irony.
The opinions expressed in this commentary are solely those of Alexandra Munroe.