Bethlem Hospital museum shows how art can help mental health
18 February 2015 Last updated at 00:11 GMT
The Bethlem Royal Hospital in south London is the world's oldest psychiatric institution, treating patients for nearly eight centuries.
Previously known as Bedlam, over the years the hospital has acquired a huge and significant collection of art and artefacts, much of it by patients.
For years it has been stored in unsuitable temporary accommodation.
On Thursday a new £4m gallery and museum to show off the collection opens to the public.
BBC News was given access to the new space to see how art can play a role in mental health and met one former patient whose work is included in the exhibition.
Video journalist: Joe Inwood