So what exactly do dwarves do when not out adventuring, drinking lots of ale and singing songs about gold?
They build fantastic underground cities, that's what. Then invite Dreamworlds to drop by and map them!
This product consists of a wealth of maps and floorplans covering the entire underground City of Dolg - 40 maps covering 17 levels and thousands of chambers. It begins with a brief history written in scholarly style by a surface-dwelling academic - if you choose to use the city 'as is' you could supply this as an in-character account that diligent characters could find through research before visiting Dolg - and then provides further detail for the GM on how the city is laid out and some of the ways in which you can use it. Perhaps it is a flourishing community with which the characters wish to trade or establish diplomatic relations, it may be under threat and needing the characters' help, or it may be a deserted ruin with few traces of its former grandeur...
An overview plan (side elevation) and a surface map is followed by a host of level and sub-level ones, all drawn clearly but in a neat hand-drawn style. The areas on each level are numbered with a brief key that gives the suggested use of each chamber. There's a lot going on - trading and residential areas, a military section, forges and warehouses, extensive coal, silver and ore mines, a royal palace, and even a cemetary complete with embalming facilities. It is perhaps a little short on santitary facilities, we hope that the rather few chambers designated as 'closets' are well-signposted for dwarves in search of relief!
Appendices cover details of mine shafts and the railway system that serves to transport rock and metals around the city, quite an engineering feat - as is, indeed, the entire city.
If dwarves in your campaign world construct underground cities, here is one ready-made, and a fine one at that. However you decide to use it, it is an impressive and coherent place that should provide plenty of memorable adventure.