They were scrapped almost 7 years ago - now they're back.
London's iconic double-decker bus has been given a million pound makeover by the capital's mayor Boris Johnson.
This fleet of 8 buses are prototypes.
The project cost almost £11.5 million pounds that's the equivalent of £1.4 million a bus.
Transport for London boss Mike Weston says it's money well spent.
"The other buses in this garage here would have cost similar amounts to design and develop. The difference in this project is that TFL have paid that cost upfront but we'll reap the benefits when we start buying production buses because the production buses will be cheaper then they would have been."
But not everyone agrees.
London's former mayor, Ken Livingstone, says the money could have been better spent.
"We should be looking at electric buses so that we don't get the pollution. In this city about 4,000 people at least die prematurely each year and that's not just a few weeks or a few months on average it's 11 years of their lives."
Double deckers were originally built in 1947 to replace the World War two trolly buses.
They became a familiar site on London's streets.
The new Routemasters still have the popular hop on hop off platform at the rear.
And they'll also have a conductor - to offer travel advice.
But the biggest change is the engine.
The new buses have fuel efficient hybrid diesel-electric motors.
The full fleet is expected to be in operation by May, just in time to help ferry the millions of extra visitors coming to London for this summer's Olympic Games.
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