Buildings ranging from a works canteen which is a listed building, to an Iron Age Fort, will be opened to the public.
For four days owners of dozens of historic buildings will be inviting the people of Leeds and beyond to enjoy them for free.
The open days are staged by the guardian of the city's architectural history, Leeds Civic Trust. The open days are also part of a nationwide series staged in towns an cities across the country. In Leeds thery take place from September 11 to 14.
The Leeds open days are amongst the most comprehensive in the country, and are backed by Leeds City Council.
The trust and council have encouraged the owners, managers and guardians of historic houses, green spaces, theatres, libraries, museums, railways and places of worship to show them off free of charge to the public.
At the same time experts and enthusiasts will lead walks and tours introducing people to many aspects of the heritage of Leeds and its district. This year there are over 70 openings and events in Leeds Metropolitan District, and several specifically provide for children.
Families will be able to go behind closed doors at the new Leeds City Museum, the City Varieties, the Carriageworks Theatre, Otley Courthouse and the Grand Theatre.
The list includes at Barwick's Iron Age Fort, Roundhay Park and Gipton Wood, buildings of all ages, ranging from Anglo-Saxon All Hallows Church in Bardsey to a 1990s eco-house in Chapel Allerton. St Wilfrid's Church at Halton is one of the many places of worship opening specially for the event.
Also included are book collections at the University of Leeds Brotherton Library, the Georgian Leeds Library and at the Thoresby Society.
Other collections can be seen at the International Textile Archive, Harewood House and Lotherton Hall.
The "star of the show" this year will be Braime's Pressed Steel Works, the highly distinctive red brick and terracotta factory on Hunslet Road which opened in 1913.
The building has ornate Burmantofts Faience features, including its canteen which is one of the only grade-two listed factory canteens in the country.
At 10 am on September 9, as a preview to the open days, Nicholas Braime, the managing director of Braime's Pressings Ltd will be showing civic dignitaries and members of Leeds Civic Trust around the building.
Leeds City Council is opening its museums to the public free of charge during the weekend.
Lynda Kitching, vice chairwoman of Leeds Civic Trust said: "The trust is delighted that so many building owners and organisations have responded to our call to become involved. It is a great opportunity to show off the fantastic heritage of Leeds and its district. I think many people will really make a special effort to visit five or six buildings and to go on some of the walks. There are more than 70 activities to choose from."
Leaflets providing a list of the buildings which are open and other activities taking place are available from Leeds Visitor Centre at City Station, all libraries, the Carriageworks Theatre and at Leeds Civic Hall information desk.
And, properties across North Yorkshire are also opening their doors for free.
Amongst 80 local highlights are the chance to:
l Discover how Harrogate became a famous spa town at the Royal Pump Room Museum. Try the strongest sulphur water in Europe and discover Victorian life and ancient Egyptian treasures;
l Step back in time to 1939 at Scarborough Castle and find out what life was like for children evacuated from the big cities during the Second World War by joining an evacuees picnic, complete with costumed guides;
l Meet the residents of historic fishermen's cottages at The Cragg, Whitby, dotted along a narrow elevated lane below the evocatively-named Khyber Pass;
l Discover one of York's most beautiful secret buildings, the church of St Martin-cum-Gregory, Micklegate, set to become a national centre for stained glass and fine craftsmanship.
Alex Markham of English Heritage said: "The wealth of events taking place in North Yorkshire is breathtaking, offering a great opportunity to celebrate our beautiful, quirky and inspiring heritage and culture.
With many properties opening for the first time and all of them free of charge, it's a great incentive to explore."
Last year's open days attracted nearly a million visitors. Around 90 per cent of the population live within 30 minutes of an event. Times, dates and directions are at www.heritageopendays.org.uk.