Twin brothers who built the world's biggest model railway are celebrating a massive grand prix win after persuading the real Prince Albert to open their mini Monaco.

Frederik and Gerrit Braun spent 23 years and around EUR 21 million (GBP 17.7 million) crafting the Miniatur Wunderland in Hamburg, Germany.

The astonishingly detailed creation is so large it is spread out across several warehouses and has become one of Germany's biggest tourist attractions with more than 70 million visitors.

The 1:87 scale railways take visitors on a whistle-stop tour of the world with sections in Brazil, the USA, Germany, Switzerland, Italy and a host of other countries.

It won the Guinness World Record for the world's largest model railway in 2015.

Now, the twins have won an F1 podium place after getting Prince Albert of Monaco to open a new EUR 5 million replica of his principality's race circuit.

Albert, wife Princess Charlene and children Prince Jacques and Princess Gabriella had a special view of the pocket-sized principality in April.

One picture from the opening shows Albert peering into a miniature recreation of his Prince's Palace.

As model trains glide past, replica F1 cars jockey for position as they roll around the street circuit alongside them.

Gerrit Braun said: 'We had this vision of recreating the Monaco Grand Prix with real little Formula 1 cars racing in it.'

Miniatur Wunderland added: 'The absolute highlight is the Formula 1 track, aversion of which has been in the works for 11 years.'

In another painstakingly accurate recreation, the brothers built a mini replica of Rio de Janeiro's Christ the Redeemer statue.

The entire railway has more than 1,000 trains pulling more than 10,000 coaches with tracks spanning several hundred miles.

Coastal sections sit in a huge pool of 30,000 litres of water and the entire system is computer-controlled down to the last signal box.

It has more than 250 moving cars that can react to each other in traffic as well as airports.

One has already been declared the largest miniature airport in the world and uses software to control 40 aircraft that take off and land all day long.

Eagle-eyed visitors can spot nudists, exhibitionists, killer sharks, James Bond, Mary Poppins and even E.T. among the huge crowds of model people.