It is a miracle that there has been no accident here

Park director Jaromir Krajewski

The viaducts were built from an experimental form of concrete early in the last century, and are rapidly deterioriating.

Conservationists say bungee jumpers are risking their lives, as well as damaging the historic structures.

"It is a miracle that there has been no accident here", the director of the Puszcza Romincka area of outstanding natural beauty, Jaromir Krajewski, told the Polish Press Agency.

Fine

He has imposed a fine of up to 5,000 zlotys ($1,200) for anyone caught bungee jumping from the bridges.

A patina of decay shows on one of the viaducts

Bungee jumping took off in Poland in a big way in the 1990s.

Cranes above the sea in the port city of Gdansk are one of the most common jumping-off platforms.

However the viaducts, at Stanczyki, close to the border with the Russian enclave of Kaliningrad, have also become popular.

At 31.5m high and 105m long, they are the highest railway viaducts in Poland, though no trains have crossed them since the Second World War, when the area was known as East Prussia.

Wood and concrete

The railway they supported was one of several in the area dismantled for materials by Soviet forces in the wake of their advance deep into Nazi Germany in 1945.

The defunct trackbed, unused since 1945

But post-war border changes and population shifts deprived the line of potential traffic and so the Goldap-Zytkiejmy line was never rebuilt after the war.

The viaducts were built using an unusual form of concrete construction, with the reinforcement being provided by inserted wooden beams without any metal, and have moulded, decorative parapets.

One of the viaducts dates from before 1914, the other was built in 1926, but no maintenance has been carried out since World War II.

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