[Raellus]

There are 26 canon adventure modules, by my count, but polls are limited to 20 options, so I've omitted the later modules and anything that could be more rightly considered a sourcebook (like Howling Wilderness). You can always choose "Other", if your favorite wasn't listed.

I'm partial to Pirates of the Vistula, mainly because I ran it as a PbP for over 6 years. This included an extended episode in Warsaw, using elements of the Ruins Of... module. This epic campaign also inspired me to create my own adventure module, set in northern Poland, Rook's Gambit.