In Norway, the thieves rappelled through a glass ceiling. In Stockholm, they set fires to distract the police. And in a predawn raid on a French chateau with more than 1,500 rooms, it took just minutes for them to find what they were looking for.
The target of all these daring heists was the same: Chinese art that had been taken by Western powers under colonialism and which in recent years has become a matter of national pride for China's government and its nouveau riche.
So is the Chinese government behind one of the boldest art-crime waves in history?
On the seemingly expert planning and techniques behind these heists
"It's pretty incredible the methods they seemed to have worked out. There's definitely a very clear methodology between all of these heists, which occurred in Europe starting around 2010 and up to the present day.
"You see often that they're lighting cars on fire to distract the police, sort of taking their attention away from the crime scene, and then smashing into these high-profile museums. They're coming in, you know, rappelling down glass ceilings, they're smashing in through side doors. Anything they can do to get to the art, they're figuring it out."
On how the thieves are largely ignoring the most expensive works, stealing art associated with China instead
"One of the most interesting parts of this is there's security camera footage from at least one of these thefts, and you can see that when they break in, they know exactly what they're going for, and that's how they can get in and out in two minutes, six minutes, seven minutes.
"They're passing up much more valuable art in favor of pieces that have some connection to Chinese history, and especially this history of defeat or humiliation that the Chinese feel between the century of 1840 and 1949, what they call the Century of Humiliation, when China was invaded and carved up by foreign armies. During that period, a lot of art was taken by Western powers to be displayed in these resplendent museums back in the West, and it seems like whoever's breaking into these museums now, they want to make sure they take those pieces back, and they're willing to leave much more valuable pieces that don't have that provenance.”
On the variety of art being stolen
"Some of these are imperial seals. There are dragon carvings There are Buddhist statues. This stuff really runs the gamut, and if you believe some of the numbers the Chinese put out, there have been perhaps millions of objects taken from China since 1840. So, anything you can picture — big, small paintings, tapestries, statues — it's in some Western museum.
"Where exactly that line is between patriotism and crime and capitalism — it's a blurry one, and that's what makes it so interesting."Alex W. Palmer
On who is believed to be behind the thefts, free agents or the Chinese government
"The line here between commerce and crime is a really thin and really blurry one … For many years, the Chinese have been talking about their desire to reclaim this art, and they had sort of pulled out bulletins to Western museums, saying, 'Hey, you should return this stuff.' But it really got serious in about 2009 when the government started sending out what it called the 'treasure hunting teams' to museums across the West, like the Metropolitan in New York, and then to some of these European museums that ended up getting burgled.
"These were researchers, members of the Communist Party, who were looking for items with some connection to Chinese history or that had been looted from China, and the next year in 2010, you see the thefts start to occur across Europe. Now, of course ... there could be free agents.
"Where exactly that line is between patriotism and crime and capitalism, it's a blurry one, and that's what makes it so interesting."
On the response from the Chinese government to the heists
"Beijing alternately says that they want these pieces back, that the methodology of their return does not matter, and then they're very mum about these specific thefts. You'll see them saying that they don't like thefts, because it only encourages more stealing, and they're worried essentially that items will get broken when thieves are trying to steal them or transport them.
"They also don't have too much sympathy, as you can imagine, for these burgled Western museums. One of the comparisons I heard a lot during this reporting was there's no compunction about returning items that were taken by Axis Powers during World War II. That's seen as proper restitution. Why is it not the same case that China was stolen from in the 19th century? Why is it OK just because it happened a century earlier? Why do we allow it?
"That's something that Western museums and now perhaps these thieves are questioning themselves."
"Now, as China has gotten bolder in recent years, gotten more powerful ... much less fervent about destroying the old, they have a much clearer interest in this stuff."Alex W. Palmer
On the issue of Chinese art in Western museums, and its importance to Beijing
" ... when China was more in the midst and throes of revolution, when there were purges and people were being sent to the countryside for decades and decades under Mao, Western museums were basically saying, 'Look, China is not a safe place for this heritage right now. They can't protect their antiquities.' And in fact, there were programs to destroy what Mao called the 'Four Olds,' one of which was old culture. So people were smashing museums, they were smashing these valuable vases and priceless works of art.
"Now, as China has gotten bolder in recent years, gotten more powerful and certainly gotten richer and much less communist, much less fervent about destroying the old, they have a much clearer interest in this stuff, and especially for the Chinese Communist Party, which has really latched its legitimacy onto the idea that it can bring China back from what had been a century of humiliation. These items are very visible proof that they're restoring the country."
On why people don’t buy the art instead of stealing it
"In a lot of cases, they do, and you'll see some incredible auction buys in recent years, just millions and millions of dollars ahead of what people had valued an object, that, because it has some Chinese provenance, all of a sudden you have buyers from mainland China swooping in and spending, you know, $30 million, $60 million on it.
"But, that's not always possible. In a lot of cases, the most valuable and the rarest works of art are never going to go up for auction, so they're either held at Western museums, or they're held in private collections, and especially these items that China feels the most strongly about — that were taken from the Old Summer Palace when it was looted by the British and the French — those items really ended up in royal collections. They ended up in palaces in France and Britain. They were given to kings and queens, and those are never going up for auction, so if you want them, there's only one way to get them — and that's not legally."
On the security measures museums are now taking to prevent theft
"There have been a few different reactions … One of the places I've visited, the KODE Museum in Bergen, Norway, has the especially auspicious distinction of having been robbed twice. Its China collection was looted in 2010, and then a few years later by thieves looking for specifically these types of items with a connection to China. So they hired a security director after the second theft.
"He came in and did ground-to-ceiling reform of the institution, and they actually are still under construction and putting in new security measures, so the China exhibit is still closed.
"But then you also have others that are quietly sending back items that they think might be attracting the attention of these thieves or of the Chinese government, maybe things that they always felt a little bit ethically queasy about, and now they have sort of a good excuse to send them back.
"Partly, that seems to be, for some collectors and for some museums, a way to get in the good graces of the Chinese government … So, museums and collectors, they're still trying to figure out exactly what's happening and how to navigate this new situation."
This segment aired on August 28, 2018.