Abigail SaltmarshThe venues have been prepared and extra staff are on standby - some of Norfolk's most historic locations are ready to throw open their doors to visitors free of charge.Abigail Saltmarsh

The venues have been prepared and extra staff are on standby - some of Norfolk's most historic locations are ready to throw open their doors to visitors free of charge.

Heritage Open Days begin on Thursday, September10, and for four days members of the public will be able to explore some of the county's most exciting locations and discover some of the secrets behind its past.

This year, for the first time, Heritage Open Days is being run by English Heritage which stepped in to rescue it when previous organiser, the Civic Trust, went into administration earlier this year.

Across the country, around one million people are expected to book to visit thousands of properties of every style, period and function that will be opening their doors for free.

Baroness Andrews, OBE, chairman of English Heritage, said: 'Heritage Open Days are thrilling. They are an opportunity to explore places which, however familiar, are normally closed and therefore mysterious.

'They provide a chance not only to discover secret history, but to meet the people who live or work there, and are passionate about their subject.

'And, of course, because there are so many of these places, and they are so very different, they demonstrate that the great wealth of our culture and history is all around us - on every street and under our feet - and that we can explore for ourselves.'

Simon Tansley, English Heritage visitor operations supervisor in the east of England, said: 'I have had great pleasure in coordinating Heritage Open Days for English Heritage sites throughout the east of England, and I am delighted that we have such a wide range on offer, including three sites in Norfolk that are participating in the event for the first time: Grimes Graves near Thetford, Greyfriars Cloisters in Great Yarmouth and Berney Arms Windmill just outside the town.'

Along with the Pleasure Beach rollercoaster, Royal Naval Hospital and St Nicholas' Church, there will also be a Fish'n'Ships guided walk along Yarmouth's South Quay, while the Lydia Eva, the last fishing drifter in Yarmouth, will be open to the public.

Other Heritage Open Day events in Norfolk include a history fair at St Edmund's Church in Downham Market, and the opening of the Boileau Mausoleum, at St Peter's Churchyard, in Ketteringham.

In Norwich, Screen East, Millennium Plain, will be screening East Anglian archive films throughout Thursday, Friday and Saturday.

Griff Rhys Jones, former president of the Civic Trust and Heritage Open Days champion, said: 'The whole idea appeals to our innate urge to get inside and poke about.

'It's what architecture is for, to experience and to explore interior space. I can't wait for this year's event.'

A full list of Norfolk's attractions open during Heritage Open Days can be found at www.heritageopendays.org.uk - for some events it is essential to book. Information on how to do this is on the website.

HIGHLIGHTS

t Wymondham Abbey: Founded in 1107, the building is distinguished by its 12th-century nave arcades, magnificent 15th-century angel roofs and 20th-century altar screen. Open Thursday to Saturday, 10am to 5pm, Sunday 1pm to 5pm. No booking required.

t Berney Arms Windmill: Have a look at one of Norfolk's best and largest marsh mills. Berney Arms Windmill was built to grind a constituent of cement and in use until 1951, finally pumping water to drain surrounding marshland. Open Sunday, 11am to 4pm. No booking required.

t Beating the Bounds: A new event has been added to the programme, Beating the Bounds, a guided walk about the Georgian parish boundary markers on Friday at 2pm and Saturday at 6pm by David A Berwick (author of Beating the Bounds in Georgian Norwich). The tour lasts about 90 minutes. Booking required.

t True's Yard Museum, King's Lynn: This is a community museum that features two Georgian fishermen's cottages and shows how the Northenders lived in the 19th century. There is also a shop and a caf�. This year there will be a special Nelson exhibition to celebrate his birth in Norfolk in September 1758. Open Sunday, 10am to 4pm. No booking required.

t Greyfriars Cloisters, Yarmouth: These are the remains of a 13th-century Franciscan Friary tucked away in Row 92, off the South Quay, one of the town's old network of narrow alleyways. This tour will give an overview of the site and how the changing face of Yarmouth is reflected within this fascinating site. Thursday and Friday, 10.30am to 11.30am. No booking required.

t Grimes Graves: Experience an unforgettable visit to Britain's only accessible prehistoric flint mine, dug by Stone Age miners 5,000 years ago. Descend more than 10m into the galleries where flint was mined for tools and weapons. Wonder at the courage and ingenuity of our distant ancestors and discover more than 400 pits, forming a lunar landscape amid the unique Breckland environment. Open Saturday and Sunday, 10am to 5pm. No booking required.

t Boileau Mausoleum, St Peter's churchyard, Ketteringham: This is a square Greek Revival mausoleum built in brick with limestone dressings and roofed with large slabs of stone. The Boileau coat of arms is carved on the keystone over the entrance and there is an iron door. The design was said to have been almost a copy of the now demolished Bevan mausoleum formerly in Nunhead Cemetery. It is open Saturday, from 9am to 6pm. No booking required.

t History fair at St Edmund's Church, Downham Market: This is Downham's only grade I-listed building. Rebuilt in the 13th century on a high vantage point overlooking the Fens, it has been enhanced by succeeding generations. It has an angel roof with the addition of saints, kings and bishops. The stained glass dates from medieval and Victorian periods and the wall monuments include a war memorial Roll of Honour painted by local artist George Smith. The tower has a peal of eight bells which will be rung on the day of the fair. Stands at the History Fair will be representative of history groups. Other events will include craft demonstrations, town walks, and children's activities. Saturday, 10.30am to 4pm. No booking required.

t Lydia Eva, Yarmouth: She is the last steam fishing drifter. Open 10-4 on Thursday. Booking is required.

t Yarmouth's Pleasure Beach: Take a ride on the rollercoaster, the gallopers or another historic ride. The rollercoaster was built at the park in 1932 and has been operational ever since. It stands and operates as the only remaining ride of its kind in the UK - and one of only eight in the world. Open from 11am to 3pm on Sunday. Booking is required, call 01493 846346.

EXPLORE NORWICH

The historic city of Norwich has a wealth of hidden heritage on offer. Here are a few highlights of this year's Heritage Open Days:

t The Bear Shop Secret Garden, Elm Hill: The Bear Shop is inviting people to have a look at its secret garden, which was based on a design by Gertrude Jekyll, an Edwardian writer and garden designer. Bring a book and a packed lunch if you want to! Open 10am to 5pm, Thursday to Saturday, and 11am to 4pm on Sunday. No booking required.

t St Catherine's House, St Catherine's Close, All Saints' Green, Norwich: A fine Georgian house designed by Thomas Ivory, with one of the first cantilevered staircases in the country. It was formerly occupied by BBC Norfolk and is now the home of Clapham and Collinge Solicitors. Tours throughout Thursday and Friday. Booking required.

t Watergate Room, Pull's Ferry: Pull's Ferry dates to the 15th century. The Watergate Room is situated over the archway which leads to the west bank of the River Wensum, and is opened by Norwich Division Girl Guides. Thursday to Sunday, 11am to 5pm. No booking required.

t The Ihsan Mosque, 17 Chapelfield East, Norwich: The Ihsan mosque was the first mosque in the UK to be owned by British Converts to Islam. Built in 1876 (as a boys' school), today it has a friendly, welcoming and refreshingly serene atmosphere. Open 5.30pm to 6.30pm Thursday, 2.30pm to 3.30pm Saturday and 2pm to 3pm Sunday. Booking required.

Royal Norfolk Regimental Museum, Market Avenue, Norwich: Find out about the everyday lives of Norfolk soldiers and their families. Follow their stories around the world through 300 years of war and peace. Get an insight into the campaigns through powerful displays of equipment, souvenirs and archive images. Open 10am to 4.30pm Thursday and Friday, and 10am to 5pm, Saturday. No booking required.

t St Peter Hungate, Princes Street, Norwich: This medieval parish church was reopened to the public in April as Hungate Medieval Art. The church now houses exhibitions and hosts events which promote Norfolk's wonderful medieval heritage. Open Saturday, 10-4. No booking required.

For more information on available tickets or to book, visit www.heritagecity.org/hods