Two videos have made their way into the BBC’s most watched list today both on boundary walls. The first sees Frank Gardner head to Saudi Arabia where they’re in the process of sealing the ‘troubled’ border with Yemen across a 1,000 mile stretch. The second marks 15 years since the Good Friday Agreement with a discussion of the ‘Peace Walls’ that divide Northern Ireland along religious lines.

Each time I return to thinking about politics, territory and space I think of Jonathan Olley’s majestic Castles of Ulster photography project. The photo above is from this very series (a short review in the Guardian from 2007 is here). I saw a selection of them at the Whitworth Art Gallery in Manchester and was blown away by their composition. They really do capture everything that is haunting about military occupation, boundary-making and the sheer architectural brutality of territorial dispute.

A corrected in-press version of a Political Geography paper on ‘Interventions in the political geography of walls’ (subs. only) by Karen Till and a selection of other authors is a handy guide to reading all the above together.