German customs officers at Frankfurt Airport say they recently discovered 2,164 fake luxury watches that were in transit after arriving on a flight from Hong Kong.

The value of the watches, if they had been genuine, has been estimated at around €170 million ($176 million), The counterfeits were so good that it took some time for airport customs officers to confirm that the timepieces were, in fact, fake.

The haul was unearthed on October 24 after the shipment was intercepted before it was sent on a connecting flight to North Macedonia. The discovery was only announced on Thursday, however, after the verification process had been completed.

“Falsifications of watches are often not recognizable at first glance,” explained Christine Straß, a spokesperson for the German federal customs agency, or Zoll, at Frankfurt Airport.

Straß said officers had to work with eleven manufacturers of genuine luxury watches and to identify and look for secret counterfeit features that are built into the genuine article. It was only by doing this that the fakes could be identified.

Straß says all 2,164 fake watches will now be destroyed.

The Zoll confiscated 265,086 counterfeit items at Frankfurt Airport last year. The vast majority of fake goods were imported from China, as well as Turkey, Hong Kong, Taiwan and Singapore.