Think Again is a new strand where we give filmmakers a space to explore radical ideas.

It's part of This Week's World, a new international affairs programme on the BBC.

In this edition, Lebanese architect and satirist Karl Sharro explains how he thinks trains can bring prosperity, exactly 100 years after the Sykes-Picot agreement was signed by colonial powers to draw borders in the Levant.

You can watch This Week's World every Saturday on BBC Two and BBC World News