Bletchley Park, the home of the Enigma code breaking machine used in the Second World War, has won a £4.6 million lottery grant.
The money, from the Heritage Lottery Fund, will be used to build a major visitor centre and to restore the code breaking facilities.
Carole Souter, chief executive of the Heritage Lottery fund, said a new exhibition at the site will feature state of the art interactive displays.
"The complex story of Bletchley Park revolves around a group of dedicated men and women who quietly worked away with no expectation of public recognition,” she said.
"Now, more than 60 years later, the trust will bring to life fascinating tales of the ground-breaking work that took place in this sprawling country estate.”
In March, Bletchley Park also won a £250,000 government grant in order to help it repair buildings at the site.