The Concrete Pourer's Art

It may not look pretty and bits of it may be falling on unsuspecting passers-by but this is, or claims to be, the first ferro-concrete building built using the Hennebique system (that's reinforced concrete to the layman). Despite the blue plaque Wikipedia reveals that the first such building was in actually built in  Swansea though that one was demolished. This building is protected and a request to demolish it was turned down. So here it stands empty and peeling at the edges but otherwise so well built it's well nigh indestructible.