High Five: 5 European foods you might not think are delicacies

Some can't bring themselves to take a single bite. Due to the putrid stench, manufacturers advise that cans of Surströmming should only be opened underwater. The stinking Swedish fish ferments for weeks — a process that continues in the can, which bulges noticeably on the supermarket shelve. Allegedly, some airlines even prohibit the rotten fish on planes due to the risk of explosion.

The Greenland shark can grow up to 400 years old. Unless it ends up as hákarl on a plate. While the shark's meat is actually poisonous when fresh, it becomes edible if you bury it or let it rot in a box for weeks. Dubbed by some the worst tasting food in the world, hákarl has a rubbery consistency and an ammonia-like flavor. It's a traditional specialty in Iceland.

Once they were a delicacy in Central Europe, but today bull testicles are only savored by experimental gourmands and very rarely appear on menus — or as in this photo, hidden in a salad. Which might be a pity, as connoisseurs describe the dish's very delicate consistency and a subtle nutty taste. In addition, bull testicles (known as Rocky Mountain oysters in the US) are rumored to boost libido.

The ingredients of this mariner's dish from Northern Germany are harmless: potatoes, beetroot, meat and fish. But after they are put through a meat grinder, it comes out looking like someone has just been sick. Labskaus is therefore often hidden under a fried egg. The specialty was born out of necessity — as sailors once lost their teeth due to vitamin deficiencies, their food had to be pureed.

A specialty on the Italian island of Sardinia, where it's known as Casu Marzu or "rotten cheese," flies lay eggs in the immature sheep's cheese before it becomes infested with live larvae, or maggots — which gives the cheese its incomparable taste. Though the delicacy is officially banned in the EU, many Sardinians do not want to give up this uniquely putrid pecorino cheese.