Over the weekend of 8 to 11 September, Heritage Open Days are providing members of the public with unique access to visit and explore some of the best hidden historical, architectural and cultural gems up and down the country, thanks to the help of thousands of local volunteers.

Here is a run down of our top 5 secret locations that you absolutely must visit – and best of all – they are all 100% free to attend.

1. Dr Johnson's House, London

Visit the real 300-year-old town house of Samuel Johnson – writer and compiler of the great Dictionary of the English Language – in a tranquil location right in the heart of the historic city of London.

Open to the public is a fascinating research library and some beautifully restored quirky interior features.

With a children's guide and a dressing up box too, this London hotspot is great for the whole family.

[Related story: Hidden gems: 7 small UK villages which are big on charm]

2. Jephson Gardens, Warwickshire

Why not visit these gorgeous Warwickshire gardens boasting beautifully colourful flowerbeds, Victorian sculptures, a sensory garden and even a pretty glass house to boot?

The 19th century Garden Lodge will play host to an exhibition on the history of Jephson Gardens, as well as a unique local history exhibition.

For active day-trippers, Leamington History Group will be leading two historical walks.

3. Bristol Blue Glass, Bristol

Intrigued to find out how glass is really made?

At Bristol Blue Glass you can attend talks, demonstrations and even make a trip to their glass shop at the end, where you can find stunning handmade jewellery to take home with you as a souvenir.

Better yet, you can have a go at blowing your own Bristol Blue Glass bauble.

4. Naburn Lock, North Yorkshire

On the River Ouse just six miles from York sits Naburn Lock.

This lock and weir is considered one of the most impressive feats of 18th century engineering, built in the 1750s.

One of these workshops contained a large blacksmith's hearth and bellows which you can still visit today.

5. Arlington Court, Devon

This secret spot was not only home to the Chichester family for over 600 years, but also contains fascinating collections reflecting Miss Rosalie Chichester's personal passions, as well as ships and shells.

The Carriage Museum is a fun and interactive experience bringing coaching history to life.

In the original kitchen-garden, produce for the tea-room is gathered, whilst the conservatory's striking plantings represent the family's extensive travels.

There are also beautiful nature walks and woodland areas.

Where are your favourite lesser-known spots? Let us know in the Comments section below.