No that title isn't a joke. This is really is a LEGO model of the London sewers. Or at least part of them.
The London sewers are an impressive architectural project that naturally goes largely unobserved. James Pegrum has produced this model of Joseph Bazalgette standing at the exit of the Fleet River in 1865 at the completion of the sewers.
Of extra special note in this instance is the incredible lighting for this photograph.