It has been a site of worship for centuries. A monastery was built there in the early Christian period, then, more than 600 years ago, it was converted into a Muslim shrine to the prophet Jonah.

There is a hill in the northern Iraqi city of Mosul called Nabi Yunus.

Engraving from Robert Brown's The Countries of the World (1876)

In July 2014 this shrine was blown up by the Islamic State (IS) group.

Militants claimed that Nabi Yunus was no longer a place of prayer but of heresy.

Footage of the explosion was beamed around the world. The message was clear: no holy site, however venerated, was safe from IS’s radical interpretation of the Koran.

But the destruction of Nabi Yunus has far from ended the story of this ancient venerated mound. Instead it has raised fascinating questions about what exactly lies beneath the foundations of the mosque.

In Spring 2018, BBC Arabic sent a team into the complex of cool, dusty tunnels recently discovered inside the hill.