Seven places you can explore underground in Norfolk

How many people visiting Norwich Magistrates' Court, for example, would know that just a few feet below them stands the well-preserved remains of a Norman house? 

Or that when you take afternoon tea in The Assembly House’s restaurant, beneath you are a maze of underground chambers once used by merchants?

Norwich has the UK's largest collection of undercrofts, but there are also other ancient cellars, passages and subterranean structures, which together represent a unique historical snapshot of the past.

The legendary tunnels that criss-cross Norwich and Norfolk might be blocked up (although those in the know can still enter some, a potentially treacherous hobby) but there are still plenty of places you can visit which are underground.

From crypts to undercrofts, cellars to mines, in our first of several pieces about accessible underground sites in the county, we look at some examples of places you can visit in Norfolk for free or for a small charge.

Seven underground places you can visit in Norfolk

1. Grime’s Graves

Named for the Saxon God Grim, Grime’s Graves is the only Neolithic flint mine open to visitors in Britain. This grassy lunar landscape of 400 pits was first named Grim’s Graves by the Anglo-Saxons. It was not until one of them was excavated in 1870 that they were identified as flint mines dug over 5,000 years ago. A small exhibition area illustrates the history of this fascinating site. Visitors over the age of seven can descend 9m (30 ft) by ladder into one excavated shaft to see the jet-black flint. The English Heritage site is near Lynford in Breckland and reopens in Spring. Visit www.english-heritage.org.uk for more information.

2.  A hidden street underground

Hidden two flights of stairs below the headquarters of The Shoebox Community Hub on Castle Street in Norwich, there are secrets to be found, abandoned houses to explore, a passageway to follow that leads to a locked door where unsuspecting pedestrians stroll past, with no idea what is just inches away. There have been whispers about what lies beneath what used to be Ponds shoe store for many years, tales of tunnels that snake through Norwich, secret dungeons where the worst prisoners of all were imprisoned, escape routes either to, or from, Norwich Castle. And in the half-light, it's easy to believe them all: the space underground is incredibly atmospheric, a warren of dark rooms and doors where it's clear to see the remains of an old yard which was once in the shadow of the castle itself. Tours cost £15 for adults, £8 for children aged four to 12 and children under four can attend for free. Book here: www.theshoebox.org.uk/hidden-street-tours/

3. A honeycomb of hidden rooms

It's a subterranean world in the heart of Norwich that was once a holding cell for criminals, 'lewd women', beggars and those fighting their own private demons and a place where children who were whipped and salted by a cruel master were brought to safety. Stone steps lead to a honeycomb of underground rooms that snake out beneath Norwich's Bridewell, the thick walls filled with the secrets of hundreds of years. Tours of the undercroft are run four times a day at 11am, 12pm, 1.30pm and 2.30pm on the first Saturday of each month. The tours are free with museum admission. The tours are unsuitable for children under the age of eight and due to steep steps and uneven floors, also unsuitable for people in wheelchairs or with limited mobility. Find out more at museums.norfolk.gov.uk.

4. Underneath Holkham Hall

Guided tours of the cellars at north Norfolk’s Holkham Hall offer visitors a chance to glimpse the warren of corridors and chambers serving the hub of the mid-18th century building, from the old bakery and the heating system to the massive wood store, which highlights the vast amount of maintenance and machinery required to maintain this great house, both past and present. Tours are available during the year, visit holkham.co.uk to find out more.

5. The final resting place for condemned prisoners

Brisley’s church towers over the nearby landscape, drawing one towards it by eye, and for good reason: this church is filled with secret treasures. There you can see gargoyles and angels, beasts and the Green Man, the Devil on high and bench carvings of foxes running away with geese in their mouths, the telltale ochre tint of medieval wall paintings and a hidden crypt where the condemned spent their last nights. Walk through the 15th century rood screen into the chancel and look for the 13th century doorway on its original hinges, which leads down into the crypt below the sanctuary. It is thought this room once acted as a charnel house, where bones of the dead were stored until Judgement Day, but in the 19th century it was a lodging house for prisoners. It was here where those destined for the gallows in Norwich were sent from King’s Lynn assizes for their last night in the realm of the living. St Bartholomew in Brisley is between Dereham and Fakenham, it is usually open daily between 10am and 4pm.

6. Underneath your feet as you eat afternoon tea

The Assembly House in Norwich stands on the original site of the Chapel in the Field which lends its name to this area of the city. The chapel was associated with the Hospital of the Blessed Virgin Mary which was built at the same time as a college and church for priests with a communal hall. Around 1278 a cloister range and crypt were built. The undercroft survives as part of the current cellars with three interconnecting rooms complete with beautiful niches for lights, a pointed barrel vault and two bays. It even has its own stalactites! The Assembly House Trust, a charity which owns the building on behalf of the people of Norwich, holds regular free guided tours of the House which include the undercrofts. These are regularly advertised on the Trust’s social media pages on Facebook and Instagram.

7.  Where gold was hidden from Hitler and a famous rebel spent his last night

It was where Protestant martyr Thomas Bilney spent his last night before being burned at the stake in 1531 and where famous rebel Robert Kett was imprisoned prior to being executed for leading a failed uprising in 1549. The vaulted cellar is one of the earliest of its kind in Britain, pre-dating the Guildhall, which was started in 1408, by at least a century. It was where tolls for the market were once kept after collection, and where Norwich's valuable civic plate and regalia were stored during the second world war. A false story was circulated, claiming the items had been sent to Wales for safe-keeping, when in reality they had been bricked up in an old fireplace, out of the Nazis' clutches. Tours are now being planned for 2023 by the Guild of Wayfinders, which began as a Norfolk and Norwich Festival 250 Project, and those who book free places will be taken into many rooms at the historic Guildhall: including the cells and the crypt. To find out more, visit nnfestival.org.uk.