The Royal Mint, based in Llantrisant in south Wales, have launched a new commemorative coin to celebrate the 50th anniversary of Decimal Day.
Decimal Day marks the move from pounds, shillings and pence to a new system of currency.
The decimal currency system was formally adopted on February 15 1971 after the Mint relocated its factory from London to Wales in order to create the new set of coins.
The special 50p design depicts sections of the old coins, as if they are piled on top of one another.
To mark the anniversary the Mint is also appealing for coin collectors to upload images of their collections to the Royal Mint website.
Dominque Evans, who designed the commemorative coin, said: "Those pre-decimal coins can still be found all over the country, in random jumbles in boxes and drawers, which led me to place together the denominations as if you had just found them and were looking at them from above.
"The sweet wren peeks out from under the crown of a threepence, sitting alongside the rose of the sixpence - all below the iconic Britannia."
Clare Maclennan, divisional director of the consumer division at the Royal Mint, said: "This year marks a significant anniversary in the Royal Mint's 1,100-year history, the 50th anniversary of Decimal Day.
"In 1966, the decision was made to evolve the nation's coinage from pounds, shillings and pence to a new decimal currency."
She called this a "major logistical exercise" and said the special 50p coin design "brings a sense of nostalgia".
The transition to decimalisation took years of planning and involved a huge public information campaign.
The Mint needed to strike so many new coins for the changeover that it had to move location. It was then that the factory relocated from Tower Hill in London to its south Wales home.
In 1968, the new Royal Mint site in Llantrisant was opened by the Queen and the first of almost six billion coins required for decimalisation went into production.
The first of the new coins, the 5p and 10p, entered circulation in April 1968 and were used alongside their pre-decimal equivalents - shillings and florins.
The new commemorative 50p coins are available to buy from the Royal Mint's website.