With recent research suggesting that spending time walking in the countryside is an effective way of relieving stress, the National Trust is offering city dwellers the chance to explore the great outdoors for free.

On March 20th and 21st, the conservation group is giving people up and down the country the opportunity to experience some of the UK’s most stunning areas of natural beauty and enjoy some clean air.

Fiona Reynolds, director-general of the National Trust, said: “Our free weekend is the perfect chance to escape the stresses of our busy lives and get outdoors and breathe in some springtime fresh air.”

As part of the promotion, the National Trust is giving away free jars of air to those who live in the city.

The air has been captured from rural walking routes and coastlines, including Lake Windermere and Box Hill in Surrey.

There are a number of beautiful locations where visitors can enjoy a good walk, with the National Trust recommending Cragside in Northumberland and Lyveden New Bield in Northamptonshire.