Historic Scotland is opening the doors of more than 70 of its properties across the country for free this weekend.
These range from castles and cathedrals to pre-historic villages and include buildings such as Dunfermline Palace.
The agency said it wanted to encourage visitors to discover more about the nation's past.
In 2007 Edinburgh Castle was the most popular monument over the weekend, with more than 25,000 visitors.
Over the 10 years the event has been running in excess of 600,000 people have visited free sites.
Peter Bromley, director of properties in care for Historic Scotland, said: "It's a fantastic opportunity for people to gain an insight into the incredible history of the nation and have a great day out with family and friends."
Culture Minister Linda Fabiani added: "I would encourage everyone to take the time to visit somewhere new that will spark their imagination about the nation's remarkable past."
A list of the properties included in the free weekend can be found at the agency's website.