Around 6,000 historic sites across Germany will open their doors to the public on Sunday.
According to the German Foundation for Monument Protection, visitors nationwide will be able to explore a wide range of sites, from historic homes and brewery cellars to church towers, factories and bunkers.
In total, more than 8,000 events and 450 guided tours are planned, with most activities free of charge.
Held annually on the second Sunday in September, the open day is Germany's largest cultural event and represents the country's contribution to the European Heritage Days, according to the foundation.
The foundation has been organizing the event since 1993.
