Listen to io9's nice sketch:
One man, walking along a route, came upon a smallish lake. It was set into a round ravine in the mountains, with steep slopes heading down into it on all sides. It looked like water had collected in the bottom of a huge bowl. The slopes were navigable, and so the man made his way down to the lake - and discovered it was full of skeletons. Hundreds of bodies lay below the surface.
The remains date back more than one thousand years. The best theory about why they rest there - in a very remote location - is that they belonged to religious pilgrims ambushed by... fierce hail.
Other explanations can leap to the Gothic mind. Ambush by rival sect, for instance, or mass sacrifice.
The world has been Gothic for a long time. Only now has it becomed Infocult.
(thanks to Tony; skull photo from Jungle Lure)