An iron ring sculpture will be part of a £630,000 investment project at Flint Castle.
The sculpture, which could potentially stand 7m (23ft) high and 30m (98ft) wide, symbolises a giant rusted crown.
It is said to represent the relationship between the medieval monarchies of Europe and the castles they built.
When opened in 2018, visitors will be able to walk along the £395,000 sculpture.
The winning design was selected by a panel following a nation-wide competition.
It will be engraved with words and sayings, to be chosen with the local community.
Flint was one of the first castles to be built in Wales by Edward I - construction began in 1277.
'Giant ancient artefact'
It was the setting as Richard II surrendered the crown to Henry IV - an event impacting the history of Britain and Europe.
"The sculpture will take a balanced form, some buried beneath the ground, the remainder projecting into the air, to demonstrate the unstable nature of the crown," said George King from the architects behind the design.
He said: "From afar its striking, iconic form resembles a giant ancient artefact, washed up on the shore of the Dee Estuary.
"However, as you approach the sculpture it becomes obvious that the piece is more than just a sculpture."
Further improvements to the castle include the installation of a stainless-steel spiral staircase within the north-east tower.
The project also includes a newly-commissioned regeneration strategy for Flint foreshore, which is still in its early stages.
Economy Secretary Ken Skates, who unveiled the design, said: "In its prime, Flint Castle played a pivotal role in not only shaping the future of Wales but that of the UK and Europe.
"The iron ring sculpture is a perfect way of marking this significance while attracting more people to visit the site, bringing positive economic benefits to the area."