From publisher blurb:
The oil-soaked bridge leaps into flames.
Skeletal hands burst from the soil and clutch at your ankles.
The massive stone you stand on flies through the air and crashes into the cloud giant as you leap off and attack.
Every battle take place somewhere, thus every battle features terrain. Sometimes all you need is a place to stand, maybe some trees or ruins to provide cover, but sometimes you want more. You want your terrain to have a major impact on the story or the heroes' tactics. You want the the Fire Swamp or the Bridge of Khazad Dum.
That's what Terrain Toolbox is for.
Terrain Toolbox provides 48 sample terrains you can drop into combat, like a blood mage's circle, solid clouds, and lightning pillars. Each sample terrain includes cosmetic and rules variations, giving you hundreds of possibilities. Plus the book offers advice to create your own terrain.