Massive sections of plastic undersea pipe — one measuring nearly a third of a mile long – have washed up on British beaches along the Norfolk coast, much to the surprise of beachgoers.

The sections of pipe were reportedly being towed from Norway to a power plant in Algeria on July 18, when a container ship ran into the tow, setting 12 huge sections adrift.

Eight lengths of the 8-foot-wide pipe were "secured and under control," according to Britain's Maritime & Coastguard Agency. The four other sections were not recovered. At least two of them ended up on U.K. beaches.

The Guardian writes: "The beached pipes have attracted curious beachgoers. ... [The] pipes are wide enough to drive a car through. Aerial footage showed two men walking on top of one of the pipes, as others took selfies."

MCA and the manufacturer of the pipes, Pipelife Norge, have warned people to stay away from the pipes to prevent injury.

"It is essential now that the salvage team fence off the pipes. If a 2.5-metre [8-foot] diameter pipe, several hundred-metre long pipe is moving in the water it is extremely dangerous," Pipelife's export manager Trygve Blomster tells The Guardian. "If you fall beside that while it moved you will be smashed. If you walk on the pipe and you drop off it is extremely dangerous."

The MCA says the pipes were not an environmental risk, but that it "may take several weeks" to return them to Norway.

A video on Pipelife Norge's corporate website shows how the pipes are towed at sea and deployed on the sea bottom.

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