Hidden gems and well-known historic sites will be throwing open their doors to visitors for free, as Norfolk's wonderful heritage is celebrated at a four-day long festival.

Eastern Daily Press: The Marble Hall at Aviva. Pic: ANTONY KELLY.The Marble Hall at Aviva. Pic: ANTONY KELLY. (Image: � ARCHANT NORFOLK 2008)

The annual Heritage Open Days event starts again on Thursday next week and will run until Sunday, with 270 events taking place across the county.

Thousands of people will be exploring hidden gems on their doorsteps, along with more familiar landmarks, such as Norwich Castle, Norwich Cathedral and The Cathedral of St John The Baptist.

Others, such as former Leper Hospital Lazar House, off Sprowston Road, and the Norwich Quaker Meeting House, in Upper Goat Lane, are less familiar, but just as fascinating.

There will also be the opportunity to look around city favourites such as the Norwich Puppet Theatre, the Marble Hall at Aviva's Surrey Street offices and the Museum of Norwich in Bridewell Alley.

Eastern Daily Press: Norwich Puppet Theatre. PHOTO BY SIMON FINLAYNorwich Puppet Theatre. PHOTO BY SIMON FINLAY

It's not just Norwich, either. Locations in Broadland, Breckland, North Norfolk, Great Yarmouth and South Norfolk are also welcoming the public to look around.

Cathy Eden, Heritage Open Days event co-ordinator, from The Forum in Norwich, said: 'After a year of planning and working in partnership with so many fantastic venues and event organisers, we can't wait for the start of this year's festival.

'There's some popular old favourites, plenty of exciting new additions and some really unusual and fun events on offer this year taking place right across the county.

'It's a once a year chance for people to enjoy, explore and discover our hidden heritage and for communities, neighbourhoods and venues to share what makes them so special.'

Eastern Daily Press: Lazar House in Norwich. Photo: Simon Finlay.Lazar House in Norwich. Photo: Simon Finlay.

The events are all free, with lots of drop-in events, where people can just turn up on the day.

Tickets for pre-booked events went on sale early in August and many were booked within minutes of tickets being announced. so it is important to call in advance to see which are still available.

The brochure about Heritage Open Days is available from The Forum, Tourist Information Centres, libraries and many other venues across the county.

It can also be downloaded here.

Eastern Daily Press: Norfolk Tank Museum. Picture: Nick ButcherNorfolk Tank Museum. Picture: Nick Butcher (Image: Archant � 2017)