Caerphilly Castle could soon be immortalised in Lego alongside world famous monuments like the Louvre and Rialto Bridge.
If successful in its bid, the 745-year-old castle would be the first ever Welsh Lego kit.
Cadw have entered a specially commissioned replica of the castle to Lego Ideas.
It has a year to get 10,000 public votes, before being considered by a panel of experts.
The model, created by Lego artist Adeel Zubair of Cardiff-based Little Big Art, features Welsh flags and the moats and leaning tower that characterise Caerphilly.
Cabinet secretary for economy and infrastructure, Ken Skates AM, said: "Wales has an incredible history that we are all immensely proud of and Caerphilly Castle is deserving of a spot in the Lego architecture range.
"I hope that the people of Wales support our bid which could see the model available in Lego stores the world over - one day we may even see a Welsh collection featuring more of our inspiring sites."
Andy Morris, owner of Little Big Art, said: "It is great to think that people the world over could have the chance to create Wales' largest castle and then hold it in the palm of their hands."