While there's nothing overtly political within its collection -- by modern standards, at least -- the museum sparked controversy when it was first announced by Hong Kong's outgoing leader Carrie Lam in late 2016, partly due to the apparent lack of public consultation before the project was green-lit.

The Palace Museum's long-term loan, which comprises rare paintings, calligraphic works, ceramics, jade and more from its 1.8 million-strong collection, is "unprecedented at every level," says the Hong Kong museum's chairman Bernard Chan.

"This is the first time ever that large quantities of these national treasures are being taken out ... to another cultural institution, so you can imagine the complexity behind it," he adds, citing challenges around transportation, security and insurance, the latter of which took a conglomerate of around 100 insurance companies from around the world to resolve.

Curating exhibitions in the midst of a pandemic also proved challenging -- as did an accelerated timeline ensuring that the museum, its construction funded by a $3.5 billion HKD ($450 million) donation by the Hong Kong Jockey Club, opened in time for this week's anniversary.

"When I was a curator in the United States, I spent three years working on one exhibition. Now I have three years to work on nine exhibitions," says deputy director Daisy Wang Yiyou, referring to the museum's ambitious opening program.

The stunning artifacts, 166 of which are considered "grade-one national treasures," feature in thematic shows, including one exploring aspects of imperial life in the Forbidden City and another focused on innovative design and production techniques. Elsewhere, an exhibition of art inspired by horses juxtaposes works from the Forbidden City with pieces on loan from the Louvre in Paris. Some of the objects have never been seen in public before, including two recently restored sketches of empresses.

Wang expects the "blockbuster" attraction to be the museum's rotating exhibition of Chinese paintings and calligraphy from the Jin, Tang, Song and Yuan dynasties.

"(These works) are extremely fragile and extremely rare, so after 30 days in Hong Kong, they are going to be escorted back to the Forbidden City storage... (to) rest for a few years," she explains.

City's changing environment for art

With 84,000 square feet of gallery space and a modern design nodding to the Forbidden City's famous architecture, the museum has taken just five years to realize. Neighboring institutions like the M+ museum for contemporary visual culture, which also overlooks Victoria Harbour from the West Kowloon Cultural District, took almost twice as long.

The Hong Kong Palace Museum was not part of initial plans for the sprawling arts district, which sits on a patch of reclaimed land and has been in development since the early 2000s. Lam's unexpected unveiling of plans in December 2016 was seen by some critics as a means to curry political favor with China's central government (she had Hong Kong's second highest job at the time). Others alleged that Beijing had applied pressure to approve the museum.

Lam rejected allegations that the project was going ahead for political reasons.

"I know that our society today is full of this type of mistrust. But for this project, we really are not motivated by self-interest," she said in 2017. "We really just hope to build a Hong Kong Palace Museum, for Hong Kong, that we can all be proud of."

The museum's announcement was nonetheless "a surprise to everyone, including myself," recalls Chan. "Nobody knew about it," he says. "But you can imagine why it was kept sort of a secret. That discussion is at a very high level."

Though the extent of Beijing's role remains unknown, the museum is in keeping with Chinese President Xi Jinping's vision of the "Chinese Dream," or "the great rejuvenation of the Chinese nation," which sees China's economic future and international influence intertwined with the glories of the nation's past. Xi has spoken on multiple occasions about artists' role in promoting patriotism and spreading Chinese and "socialist core" values. Traditional Chinese culture, in his vision, should be seen as a source of inspiration for present-day literary and artistic innovation.

During a three-day visit to Hong Kong to mark the 20th anniversary of the handover in 2017, Xi attended a signing ceremony at the museum, saying he hoped Hong Kong could promote traditional Chinese culture and exchanges between China and the West.

But the museum opens in a starkly different Hong Kong. Beijing's push for soft power comes at a time when freedom of expression is being curtailed following mass pro-democracy protests and the sweeping National Security Law that effectively brought them to a halt in 2020.

Art in the city has also been under threat, with politically sensitive works apparently censored and artists entering self-imposed exile. Several high-profile artworks addressing the Tiananmen Square massacre, including the renowned "Pillar of Shame", have been taken down in Hong Kong, which was once the only place on Chinese soil where people could freely commemorate victims of the bloody crackdown. Earlier this year, the painting "New Beijing", a thinly-veiled allusion to the death of pro-democracy protesters at the 1989 massacre, was removed from display at M+, though the museum said it was part of routine rotation plans related to "artwork condition and conservation needs."

Shared histories

Though the latest loan is a first, in terms of size, the Hong Kong Palace Museum is not the only place where the Forbidden City's treasures are exhibited. In Taiwan, which China considers a breakaway province, many of the imperial palace's most valuable treasures are currently housed at the National Palace Museum in Taipei.

Over 600,000 objects from the Forbidden City were taken to the island by retreating nationalist forces in the 1940s. With tensions between Beijing and Taipei at an all-time high, the museum is planning a drill for evacuating artifacts, should a war break out.

"I hope that one day there can be an actual collaboration between the three museums, because we are all showcasing Chinese civilization," says Chan, expressing hope that the city's new museum and its trove of treasures can transcend politics.

"Where does Chinese civilization come from? And how is Chinese civilization connected with other civilizations? Because we're not alone, right? I think that's important, especially at a time when the world is so polarized and divided."

For Hong Kong residents, meanwhile, the museum is a hot summer destination, with 100,000 tickets already sold for July. Besides offering an opportunity to see the famous objects up close, the museum's job is to make their stories relevant to local audiences, Wang says.

"It doesn't matter if you are a historian or a driver," she says. "You (can) relate to these fantastical treasures, and the stories we tell. You can be moved emotionally by the objects."

The museum opens to the public on Sunday, July 3, a day after scheduled due to inclement weather conditions. Watch the video above for an inside look into the museum.

CNN's Kevin Broad, Momo Moussa, Tom Booth, Dan Hodge and Ziyu Zhang contributed to this report.