The money will help Bletchley Park become a world heritage centre
Bletchley Park in Buckinghamshire, the top secret code-breaking hub of World War II, has been awarded nearly £500,000 of lottery funds.
The development money from the Heritage Lottery Fund will help the historic site become a world heritage and educational centre.
It is the first step towards a target of £10m to completely revamp the site.
The home of the code-breakers has been open to the public since 1994 but is in an advanced state of dilapidation.
Some of Britain's best brains spent the war cracking enemy codes at Bletchley Park, with many historians agreeing that their efforts shortened the war by two years.
The codebreakers' success allowed the Allies to know in advance what German forces were planning.
Interest in Bletchley has been growing, with nearly 100,000 visitors so far this year.
Carole Souter, from the Heritage Lottery Fund, said: "Bletchley Park is an extraordinary part of the UK's heritage.
"We... recognise the importance of preserving the site as a tribute to the men and women who worked there with quiet and tireless dedication during World War II.
"Without their dedication, our nation's history might have been a very different one."