A play lasting 11 hours and performed in French is being staged in Edinburgh in a test of endurance for audiences at the city's Festival Theatre.
Le Soulier de Satin is performed in French with English subtitles
Lasting from 1300 BST to after midnight on Monday and Tuesday, Le Soulier de Satin, or The Satin Slipper, by Paul Claudel, has three intervals.
The tale of love and religion has never been staged in its entirety in the UK.
"It's an experience for the audience," director Olivier Py told BBC Radio 4's Today programme.
Le Soulier de Satin was written in the early 1920s and has only been performed twice in the world.
"Two is a lot," Mr Py told Radio 4, but added: "What the people will hear, there's no other place to hear it."
The full 11-hour play has only been staged twice before
Set in 15th Century Spain, it centres on the love story of a knight and the young wife of a noblemen.
"The main idea is it's a love story but it's a very strange love story - the lovers never meet, they're always separated," Mr Py told Radio 4.
The play covers a huge range of subjects, he said. "It speaks about politics, love, God, art, death and so on - everything, it's the whole world.
"The ideas are so deep, so clever and so new - even now - and also it's not boring, even now."
The show involves 24 actors and musicians playing various roles, with English subtitles.
Actor Olivier Balazuc, who is on stage for up to five hours, described it as a "life experience".