Human beings generally have ten fingers. In what is probably not a coincidence, the world’s most popular number system counts in base 10.

And so, due to what was essentially a series of evolutionary accidents, the largely meaningless fact this is our 100th episode feels like A Big Deal.

But I’m a huge fan of meaningless celebrations, especially when they’re about myself. So this episode is by way of a sort of party. Former co-host Stephanie Boland is back, with one of those city quizzes she sometimes makes me for podcasting purposes.

We also have brief guest appearances from four friends of the show – my other former co-host, Barbara Speed; Centre for Cities economist and mackem Paul Swinney; Guardian journalist and noted train nerd Jim Waterson; and Skylines’ biggest fan, in Brazil or anywhere else, @AngrySigh Julia – each with a question for the two of us.

There won’t be an episode next week, as I’m off on a trip. But we’ll be back in a fortnight.

Thanks for listening. It’s really very nice that you do. 

The episode itself is below. You can subscribe to the podcast on AcastiTunes, or RSS. Enjoy.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.

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