A volcanic city

[Cheka Man]

I was thinking of a city with a lava moat, but decided at first that it would be far too hot (50C+) for anyone to want to live in. But then I thought of putting it in a very cold climate so the cold and heat balance it out and make it about 25C in the city. Mist rises constantly over the city, waste is disposed of in the lava, and fire mages in the city government have spells that can make the lava repel armies in times of war.Hot water heated by the lava is used by the city.

[Scrasamax]

Think more of a geothermal city, sitting atop hotsprings. The moat can be heated water, heated to the point that it is nearly boiling. That would probably be as effective if not quite as intimidating a barrier as a lava moat. The boiling moat could also be a meeting place where the common folk of the town come and use the boiling water to cook food in wire baskets rather than resort to boiling over a hearth or fire. Stew would be uncommon fare, but boiled eggs and chicken/poultry stuffed with lots of spices and boiled could be rather common.