Wunderland near Kalkar, Germany, cleverly combines a never-been-used multi-million-pound reactor with classic fair rides, including a merry-go-round, Ferris wheel, carousel and log flume.
A swing ride has even been fitted inside the old cooling tower, while a 130ft-high climbing wall features on the outside.
When it was originally built in 1972 the construction - dubbed the SNR-300 - was destined to be the world's most technologically advanced nuclear power plant and Germany's first fast breeder nuclear reactor.
But 12 years and more than £3 million later, the project was eventually cancelled after a series of public protests and nuclear disasters elsewhere, including Chernobyl.
By 1996 there were a few hotel rooms on the site, which gradually expanded to several hundred - as well as bars and restaurants.
Since 2002, the park has seen the addition of more than 40 rides and a museum as well as a miniature golf course and tennis courts.
A spokeswoman at the park said they received some 600,000 visitors a year and employed about 550 people during the high season.
She said: 'People come from all over the world because they are completely fascinated by the park. It's totally unique and that's what draws people in. It's not something you see every day. Some people worry it's unsafe but it is 100 per cent safe. Because the nuclear power station has never been put to use, the whole complex is guaranteed free of radiation.'
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